Every so often somebody handy at creating things wonders “hey can I build a rod myself?” normal response has been, "Get a bunch of books." Here are a few additional observations, some gained from rich experience that only comes from making mistakes, which can be far more instructive than doing things right first time. Doing something right and you only learn one way to do job; do it wrong and you learn two ways AND why right way is right way.First, like man said, get some books. One of best is L.A. Garcia's Handcrafting a Graphite Fly Rod from Frank Amato Publications. The photos are excellent. Skip Morris has maybe a more comprehensive book, The Custom Graphite Fly Rod, which as I recall from scanning it at book store, covers repairs as well as essentials. Dale Clemens's excellent volumes are encyclopedic-probably more than you want or need to know about all kinds of rods.
Then get some tools: a wrapping stand (about $30-50), a slow motor to rotate rod on stand while epoxy dries (shop for a cheap one and fit it on wrapping rig however you can), a small file, and an X-acto knife.
Materials you'll need are two kinds of epoxy, one for rod wrapping and another for making grip and attaching reel seat, and some masking tape. Something called a "bubble buster" is fun. It's an alcohol torch for popping little bubbles before they dry in epoxy on your wrappings. It takes a light touch, though, because it makes your epoxy runny and it can fry nylon thread wrappings underneath.
If you can hack $140 or so for a Flex Coat cork lathe powered by a hand drill, do it. Shaping handle on blank is a lot easier than jury-rigged methods I've tried for making grips off blank then boring them out to fit blank. The lathe lets you bore and fit cork rings one at a time, giving a perfect, on-center bond of cork to blank. Shaping grips off blank too easily leads to embarrassment, aggravation, and expense of making a new grip when you ream out too much of core or get it off center. If you get lathe now, maybe getting a friend to share cost, you can amortize cost over all rods you build.
One advantage to lathe is that you can make your grips fat, which some find makes them more comfortable than those on off-the-rack rods. If you want to slim it down later, just tape on a guide(s) to counterbalance stripping guide(s) on lower section, put it back in lathe, and sand away. (Skip Morris does rough shaping on a lathe using a high-speed Dremel tool, which invites disaster if you slip and it digs into cork. You get more control and less risk using 40 or 60 grit sandpaper for that chore.)
Now for rod itself. I suggest making a spinning rod first because your mistakes will be a lot easier to live with. When you're done, you can afford to keep it or give it away, unless you're too embarrassed by outcome. The important thing is that your brain, eyes, and hands will have learned basics of epoxy flow, wrapping, guide alignment, and grip shaping in process. Even if you can afford to do a clumsy first job on a $200 blank, why make something you don't want to fish with?