Suppressors.com or silencer.com been a while since I used it, had/has a Form 1 filing on a page by page basis, with yellow highlights, for dummies. I used their pages to get mine right, the first time out.
The can itself is really not difficult, a list as Stacked, The Big Book.
1) an external tube 8-10" with internal threads both ends, I prefer the D cell battery size tubes. Must be lettered just like a gun, same depth and size lettering and numbers with Name, address, Make and Model, Serial number. Buy on line
2) a smooth internal SS tube it's inside exterior tube for a barrel muzzle blast chamber, 1-1/12" long, Buy on line.
3) two end caps (the can muzzle od threaded only and barrel muzzle od and I'd threaded) buy on line. You call the id thread size like 5/8x24 or 1/2"x28, etc.
4) 8-9 freeze plugs stacked, auto parts store.
Nothing is drilled through the middle until you get the stamps in your hand. Then everything is center drilled, over size, preferably in a lathe, as an example only a .308 wouuld be drillled .338.
End of Big Book
If you want domed baffles you can buy a dome baffle die kit on line and a 10 ton hydraulic jack with an arbor press, square, in pieces, from Harbor Freight. Seems like the dome baffles are a bit quieter. Dome and then drill if you wish.
Nice part about building your own can and having a parts washer is just taking it apart to soak, then washing and brushing it off, in and out, reassemble and go shoot.
Basically if you can change out a drain pipe wit P trapp, under a bathroom sink, you got this.