How to: flashing doors, and vents in aluminum siding

This type of flashing is totally new to me. As I understand it the basic idea is the design the exterior siding and attach it in such a way that water would have to fight gravity to penetrate the wall/roof, and that the flashing channels water away from doors and windows, which are holes in your walls. So here are some pictures of my attempts to install flashing around the doors and vents for the solar batteries.
Battery compartment vents ready for flashing.
I cut on side of a piece of aluminum angle and folded it into the opening in the foam, between the foam and the siding.
Next I took a piece of Z-channel aluminum
and fitted it under the over-lapping sheet of siding. I cut notches in the siding so the z channel would extend beyond the edges of the vent opening.
Next I cut three more pieces of angle and fitted them into the openings, covering the layers of siding and interior angle.
And then I screwed it all into place! The rubber mallet has been a very important tool, and also the tin snips.
Here a piece of aluminum angle has been sandwiched between the insulation board and the siding, with the door frame on the back of the exposed angle. The notched the angle so that it bent over the top of the door frame, and a third piece runs across the top of the door which the siding covers.
The ISO board is attached using double sided fiberglass tape and either liquid nails or caulk (see previous post), and the aluminum siding and flashing it attached using stainless steel screws and rubber backed washers into the steel framing under neither. All of the holes for the screws are pre-drilled, and the screws hand tightened as stainless steel is rather soft and the power tools strip the heads. A dab of caulk has been applied to the backs of all the screws to prevent them from backing out.
Here is a shot of the batteries in situ under the floor on their supports. They are resting on steel covered by three layers of cork padding.

How to attaching ISO board to steel framing

I have been searching ye old internet for helpful photos and information about this phase of construction, and I found little aside from product ads. Maybe that's just how Google has tailored by internet searches based on algorithmically interpreted preferences: but I am going to put up some post of what I was looking for and didn't quite find:

How to attach ISO board to structural steel framing.
ISO board is a foam insulating board with a layer of fiber glass on both sides. I chose it because it offers more structural integrity than a traditional foam insulating board, it will hold up after being shot through with multiple screws a bit better than straight foam and it has a slightly higher R-value. I bought these sheets from a surplus building supply yard. This board will act as a structural sheeting for the exterior of the trailer, it will isolate the steel from the aluminum siding to prevent galvanic corrosion and will also cover the raised hexagonal heads of the screws used to join the framing material together.
Here is the portion of wall I am ready to cover with insulating board
The next step is to draw and cut the ISO board to cover the intended area. I used a Sharpie and a box cutting utility knife.
Okay, simple enough. Next I used a exterior double sided fiberglass carpet tape made by a company called Shurtape. I bought it @ Lowe's.
I put a few strips of the tape along the surfaces of the wall to hold the board in place while I get the siding up. It is good strong tape and has held up full 9' X 4' board for more than a week.I put the boards up into place, careful not to let it touch the tape until I was sure I had it in the right position, and then a hammered it into place with my rubber mallet, pictured on the door sill.....and then I ran a line of Liquid nails along the seams where one board meets another! Caulk works too. I have been using both.

Starting on the exterior aluminum siding

If there is one way to learn how to do something it's to try and do it by yourself in 100+ degree heat! I bought some double sided fiberglass interior/exterior carpet tape and liquid nails to hold the ISO board in place.. it has held for five days while I have worked on getting started putting up the aluminum sheet metal siding. To do that I have clamped a board to the top of the siding after pre-measuring and cutting the apertures for the wheels and tops of the trusses, then I have used ropes tied to the clamps to hoist the siding up onto the wall while standing on the floor of the bathroom/bedroom loft platform. Then I clamp roughly the middle of the metal panel and tie the clamp with rope to the roof purlins. I make pen marks every foot along the line where the stud is behind the siding and pre-drill the holes ( the 1st hole I drilled was too big and so, being COMPLETELY SLAP FLAT BROKE, and un-willing to give up, I rode around on my bike for an hour until I found enough change to buy a smaller drill bit which broke on the FIRST hole I tried to drill with it! So then I borrowed a drill bit from a friend and put up the two panels you see pictured, until that drill bit was too dull and the generator ran out of gas.) On the places where I have made mistakes, such as drilling the hole too large, or missing the stud behind, I have made some star shaped metal cut outs to cover the holes and caulked from inside. So, assuming that I will be making more mistakes, the trailer will be spattered with stars.
I got a check in the mail from The Honeypot in Asheville, NC yesterday and I borrowed a my friend Kristen of Treehouse Kid and Craft's car to go to Lowe's and buy some more drill bits, more liquid nails, tape, aluminum angle to put flashing above the windows and doors, and also some metal paint to re-paint the large white window frames. That will be a job for when I make a wee bit more money to buy another gallon of gas for the generator. This is the house that recycled hand-made fashion built.
June 15th..
It's a few days after the original post, and here are some more in progress pictures:
Self portraits with bathroom window.
All of my blankets and clothing were soaked in a recent rain-storm, so I stretched a line of bungee cords for a clothes line and put my blankets up on the roof to dry.
Full moon rising