The whole planet is my base, what are you talkin about?

To build the workbench you must have the ingredients it requires (wood and stone? or just wood?) to build it. You must first make a hammer by clicking tab, then equipt the hammer and right click switch to the second tab (I think) and there should be the workbench there, if it is greyed out you can hover or click it to see the ingredients it requires.

There is no limit to workbenches; I have built hundreds.

For the game to consider something "a base" where you get raid attacks you must have multiple objects within close vicinity of eachother (my memory wants to say 3 but I dont truely know, also no idea what exact objects).

I am yet to come across any information that has said only up to 8 locations can be raided. You are the first to mention any type of limit and being a big modder of the game myself I don't really think they have put limits on max objects, pretty much go for gold until unity/your pc can't handle it anymore.