I'm going to see if I can get some money after my School Certificate as nothing happens at school for the rest of the year after it.
Now, when buying a guitar, what should I test out?
Are there any specific settings on an amp I should try out? Clean channel? Gain?
Are there any guides on instructions on how to use an amp in general?
I haven't tried playing an electric guitar except for a few times at school.

At the moment I'm thinking of getting a Fender Strat (MIM) and a Roland Cube 20x. 30x is feasible. That will set me back around $1200-$1300 AUD. Any other suggestions on possible combos. I'm into classic rock, pop rock, punk, alt, etc. I don't like metal.

Anyway cheers.
will it be your first guitar?
A hero of war, Yeah that's what I'll be

I currently have an Ibanez PF60S-NT. It's an acoustic so I can't say I have experience with an electric.
The MIM Strat and the Cube are not bad beginner choices for your styles. You could do a lot worse. There are some alternatives in that price range so shop around first.
They are both very good choices. Maybe try a Vox Valvetronix, never tried one. But i hear they're very good.
When trying, if it has a nice feel, it plays well, and your sound if good to your tastes. You should buy it.
As far as the guitar, check to make sure the neck isn't warped/bent funny. Make sure it's comfortable. Even though you may be set on getting the Fender, I'd suggest trying other manufacturers and guitar models for just a chance to see the differences on how guitars can feel from manufacturer to manufacturer. Again, go with what feels to be the most comfortable to you.

As far as the amp, I'd strongly suggest getting the 30x over the 20x, as it's got more features, giving you much more options in playing styles and tones. Again, try out other manufactures, because tones will vary wildly between them. Vox is another amp maker you might want to consider, as well as various smaller tube amps by Crate (Palomino), Fender (Champ), or Peavey (Royal 8). Again, try before you by, and just go nuts on the settings so you can get an idea of what they could be capable of doing.
~We Rock Out With Our Cocks Out!: UG Naked Club.~
Once in a blue moon, God reaches down from his lofty perch, points at an infant boy and proclaims, "This one shall have balls carved out of fucking granite."
For the guitar, check it over well. Look for blems in the finish, how the screws look (no lopsided ones, etc), there are no crackly pots or switches, the neck pocket is tight, if the frets are in well (without over hang) how the inlays are cut, the condition of the neck (pretty straight, not warped), if the tremolo is working correctly, and setup (minor but it saves you some trouble down the road).

For the amp, pretty much make sure it works. Be sure there are no abnormal excess noises like humming and buzz that aren't from the guitar. Be sure all the controls are working correctly as well. Always try more then one of anything if possible to be sure its the one you want and to check for inconsistencies.
What are some good guitars which would be less than $839 AUD and fit under the same preferred genres? I'm thinking of getting an amp with watts.