Don't buy the kit, borrow it or find a course somewhere. It'll be
cheaper, plus the other advantages.

If you just "want something welded", pay someone to do it. If you're in
Bristol or South Wales, mail me.

Gas welding costs a fortune because UK bottle rental is a rip-off. It
applies on a smaller scale to MIG welding too. OTOH, oxy-acetylene kit
would let you use welding for steel-steel joins and brazing for
steel-brass/copper, all with the same kit.

Electric welding is cheap for manual stick (1/4" steel and upwards,
maybe 1/8" if your hand is good, but not really much lower thickness).
Wire-feed (MIG) welding is great for sheet and thicker stuff too, but
it's not cheap equipment if you want to do it right. Don't buy any new
MIG machine for under =A3300 (Cebora, Murex) - if you're getting a
Clarke or similar, buy it S/H and save some money - they're all a bit
rough at that price range.

You can't afford TIG.

You can't electric weld anything other than steel. Cast iron with
difficulty and expense. Forget it for non-ferrous cuprous, aluminium,
stainless or mixtures.

Stainless steel with silver solder beautifully with O-A, or even
propane, but the materials are pricey. For other methods it gets
difficult - wire-feed will do it, if you do it right (right wire, right
gas, right machine).

Welding is the easy bit. There's also the cutting and shaping first.
This is harder and takes a ridiculous amount of time (it has just taken
me 3 days to make two sets of hinges!)

There's no "dummies guide", because this isn't a process for dummies.
The best single book I know is Gibson's "Practical Welding"
http://www.amazon.co.uk/exec/obidos/ASIN/0333609573/codesmiths