I take it you mean steel armour....can't help ya there.

I've made leather gorgets for my group, working on leather armor for myself for next season.

You'll need something for dishing the steel. And if you really get into it an English wheel would be nice.

There is a merchant on www.armourarchive.org called Halberds that sells a really spiffy "beginner set" of metalworking tools.
Most everything is there for dishing, riveting even inside tight places, and shaping steel. You would have to acquire an anvil or chunk of RR track - Something to use as an anvil - on your own.

Just one suggestion.

assortment of hammers
auto body dollies work great instead of shaped anvil stakes
an anvil (if you are working the metal cold you can get by with a cheap made in china ASO - anvil shaped object)
good shears
you can make your own rivit setters and headers from standard bar stock from the hardware store.

You need surprisingly little equipment for basic armoring. You will probably make fluting stakes and the like as you need them.

i just use a hammer and a cheap 11lb anvil from OSH. i do my cutting with a borrowed circular saw and cutaway metal disk. i've done cutting with a chisel too, but that's just not worth it.

The following is my own opinion and method - so take with some salt, a little pepper and some paprika won't hurt, either.

I feel the best place to start in making your own armour is the design phase. Do some research and find out at least 3 different types of armour your persona would have worn. Pick one and start from there. This will help you immensely in figuring out what you need to make the armour you want.

Once that's done, then it's time to pattern the armour. Get some (a lot) of posterboard and cardboard, scotch tape, tailors tape, a long ruler and a few markers. In your research you may have found some patterns for the armour you want to make. This is good. Set up the pattern on the posterboard and get a friend to tape you into it and see how well it fits. Cardboard is stiff enough to help you find where it would bind or pinch. Remember - it's far better to mess up cardboard and duct tape than it is expensive leather or that nice stainless steel you just spent 3 hours polishing.

Once the pattern is done, then it's time to consider what tools you MUST have (to get the job done) and would like to have (to make the job a little easier). Ball pen hammers, heavy hammers, pliers and screwdrivers can be considered standard in most toolboxes. Depending on how much metal work you are doing, a jigsaw, dremel, bench grinder (with stand), drill press, hand drill, metal punch and bench vise tend to be valuable tools all over.

Most of the other tools you would need are specific to either leather working or armouring.

After that it's time to get to work.

Ideally, if there is someone local to you that does armouring - pick their brains. If you can, go to their shop (bring beer or libation of choice), watch them at work, help out here and there and see if you can ask lots of questions.

If there is not someone close, then it's time to do some experementing on your own. Use small samples to get part of what you want done. make "test parts" and see how things turn out. If you are learning on your own, there is a VERY steep learning curve - so factor in lots of trial and error.

Hope that helps some to get you started.