First get a 42mm hole cutter and cut holes in a 2x6 inch piece of drywall stud. The hole need to be cut as close to the horizontal edge as possible, but not too close to what will be the vertical edges. This will provide plenty of strength for supporting your weight, combined with a 3:2 pivot ratio on the bars. Use some long 6M or 8M screws to secure it to the wall; I have used 3 x 6M 80mm screws, which will be plenty to support my weight plus 50kg of ballast (tested using sandbag).
Next place your 40mm copper tube (use steel tube if you plan on putting a load of more than 130kg on them, I am not sure of their capacity beyond this before they will start to bend). They should sit on a slant with plenty of slack, not too tight.
Next, get your spirit level and mark a line on what will be the supporting ground post for the frame. You want to cut the post so that it is almost level with the top of the 6x4 where it is mounted on the wall. If your floor is even and level, you can just mark it by standing it next to the 6x4. I preferred a level since I didn't trust the level of the floor enough, so held it in place.
Saw the post in two, hopefully you have enough for both posts. I chopped my post roughly in half in the end and used a floor strut to retain and raise the height of the posts slightly. If you have more wood at your disposal, cut them more precisely; I actually found the floor strut makes the structure more rigid, although I fitted it later on so don't have a picture of that, but it essentially mimics what the platform strut does. Cut a 42mm hole in the top of each post as shown; doesn't need to be much material above the hole, just enough to get some screws in for fixing the platform strut.
The platform should be secured to the 6x4 attached to the wall and to the supporting ground posts. This prevents any lateral movement in the frame, keeping it sold. You only need a couple of wood screws, nothing heavy duty since there shouldn't be much lateral stress on it. Conveniently, my platform strut was already cut to this shape and size, left over from building my son a table. Just ensure you have an area cut out between the posts to allow room for your chest should you lean into the dips.
Finally you should be able to neatly insert the pipes into the holes through the posts and into the wall brace. They aren't secured and shouldn't need to be; I like to be able to remove them when it's not in use so it doesn't take up too much space. Just ensure you always check the pipes are fully inserted before putting any load on them!
Here is a quick demo of the dip-station using just my body weight. I have also tested it using my 50kg sandbag held between my legs; seems suitable for heavy loads. I may upgrade the bars to some 40mm steel tubes at some point just for peace of mind.
