Costuming (Garb 101)
Yes. There are classes. And people who are EXCELLENT at costuming. And armoring.
Still, here are the basics:
Most everyone begins with the T-tunic. It's basically a T shape, long or short depending on the gender of your persona. Add a hold for your head, maybe a key-hole neckline and gussets (squares) for your armits and there you go. For a male persona, hospital scrub-type pants work. Depending on how you add your trim and decorations, they'll work for any European persona for a range of about a thousand years. Plus, if you leave off the arms, they layer really nicely. Mix and match to extend your wardrobe.
I have found making a duct tape dressmaker's dummy helpful for fitting to my shape and size.
Fabrics should be fairly natural (cotton is okay - wool and linen are better). Silk? of course! Bed sheets and second hand store fabrics are cheap and serve well as first-attempt garb. When you are more comfortable, move on to better, more comfortable materials.
Faux fur and fur are generally not seen as trim but are inside garb, but do the research to find out what is authentic versus what is Hollywood when making and trimming your garb, so you make something you know a little about which you can be proud of.
Many times, modern belts, boots, tights and pants can be re-purposed into garb with very little effort. Check out your accessories to make them look as true to "Period" as possible. The '2-foot' rule applies. If it looks authentic from two feet away, it's okay.
Hats & Head Coverings
Mostly, women wore hair covered by something. I never could get the veil right, so I moved on to Renaissance and made braids and such with $2.99 faux hair from Sally Beauty Supply. Scarfs wrapped around the head work, too, as well as little caps called cauls. Hoods are easy to make, too. With headgear as with other garb, if you are looking for a pattern, ask. Someone has one, and is probably willing to share or send you in the right direction, saving you time and money.