Unless you have good tools or access to a shop working with steel is going to be a *.
Check out this site for some basic patterns and inquiry.
http://www.armourarchive.org/Some people swear by Armor Archives but lots of SCAdians I know find their patterns to be poor at times.
Still a start is a start and I will say it's going to be a learning experience.
Had this question asked on another thread and thought I'd preform some good ol' copy paste/mod below.
Here's a list of items you'll probably need to get if you plan on working anything that has complex curves.
Things you need:
A way to cut your metal
A way to file down the sharp edges
A hammer to beat on the metal
A stump or sandbag for dishing
An anvil or chunk of railroad track for riveting and edge-rolling
Here's some other alternatives to the above items.
Typically I've cut my metal with beverly shears but this is not a cheap thing.
I've seen angle grinders and hand shears used for cutting out your patterns but it takes a bit more time for sure.
As far as grinding down the edges; I've been using a bench grinder.
For hammering a metal or hide mallet works good. (I suggest getting ear plugs)
For dishing the best is an actual metal armoring dish but, again not the cheapest thing. So a stump with a carved out bowl is a good alternative.
Anvil and railroad track is great for riveting.
My only issue when trying to use armoring alternatives that doesn't cost tons of money is a substitution for the horn of the anvil.
I hope this information helps and gives you some form of an idea of what you're doing.