i just bought a grainfather after 41 brews - of which i did 2 all grains, about 15 partial mash, about 10 with steeping grains and finishing hops, and the earliest ones straight out of the can.
that's how most brewers start, and you can make perfectly good beer from the outset.
tips - check the useby date on anything in a can. get the newest. you'll only ever buy the 1/2 price hitting use by date sale can once. (or twice just to be sure that beer can really be so vile).
use dry or liquid malts instead of dextrose. (dextrose for bottling only). malts will give good flavours, dextrose is pretty much tasteless.
try (eg) safale 04 yeast if making an ale - then research how to save the yeast after fermenting for re-use. any of the bought yeasts are better than the ones that come with a can.
steep or boil maybe 5 - 10 gms of hops for 10 or so minutes in a separate saucepan, then strain well and add to brew. no more than 10 gms until you learn to gauge just what sort of impact it will have. remember that the can will already have hops. do a little research on which hops to add eg 5-8 gms cluster hops adds class to a qld ale can, cos that's the main hops in fourex. (and you'll make fourex look pretty ordinairy).
the hops not only introduces you to that step but it also kills the 'homebrew' taste you can get from cans.
steep some steeping grains. (research or ask you brew supplier cos some grains have to be mashed, some can be steeped. crystal malts are good for steeping (like steeping tealeaves. again, in separate saucepan, strain and add to brew. this really lifts brew cans and works great on darker beers.
going from cans to partials to full grains is a big learning curve, and you'll be in a big learning curve from brew to brew anyway.
there's a lot of timing involved on a brewday - when to sterilise this, or heat water for that, or deydrate the yeast so it's optimal at pitch. i'd strongly suggest start with the simple, get the rythym, then add little processes. and your beers will start off better than anything in a shop, and they just get better and better.
oh - finally - you won't be able to actually clone anything unless you strip all the goodness out of it. commercial beer is made at the lowest cost of product v maximum output. so, for example, i make fivex, which is one better than fourex. same recipe, but 4% alc and MASSIVE flavour.
enjoy