So i have an Ibanez tsa15h and i'm going to by a Marshall 1960 AV 4x12 cab, and then later on a JCM 800 2203. what i want to know is can i play my 15 watt ibanez head through a 4x12 cab? i have no idea about the technical stuff of amps/how or what all this ohms stuff means, probably a stupid question but o'well.
On the back of my amp there is heaps off different plugs, (2x8 ohm, 1x4 ohm, 2x16 ohm, 1x8 ohm and 1x16 ohm. my cab sais mono 8 ohm so i have it plugged in 1x8 ohm on the head into the cab. to play it through a 4x12 do i need a plug on the back of my amp saying 4x12ohm? (which i don't have)

So Basically i would just like to know if i can play my 15 watt ibanez head through a Marshall 4x12 cab, and just a wee explanation on what all this ohm stuff is and an insight into how this all works.

You've plugged it in correctly, and the amp will work fine.

Ohms are units of impedance. Basically what it means is that the output transformer of the amp is the most efficient when it is receiving a certain impedance from the speaker. Matching ohms provides the optimal match for the transformer. If you don't match impedances, the amp will run quieter and sometimes hotter, and if done for too long or into a very incorrect load, the transformer and the power tubes can blow.

As to the wattage: A cab has a maximum power handling rating. On that cab, it's probably somewhere around 100-150 watts. That's just the most power it can receive from the amp. Anything less than that is ok - so your 15 watt amp won't be a problem. A 200 watt amp, of course, would be an issue. It takes a small fraction of a watt to drive a speaker, so there's no practical minimum number of watts required to power a cab.
oh thanks, that's shed some light on all this tech stuff now =) . so the 4x12 has a switch on the back -mono and stereo. on the stereo side it sais 16 ohm input 8 ohm left. on the mono side it sais 4 ohm input 8 ohm right, what would i plug it into and also what one on my amps head?
Stereo is for running either two amps, or a stereo amp (you'll know if you have a stereo amp). Mono is what you want.

They give you two 8 ohm outs in case you want to use multiple cabs, but if you only have one, it doesn't matter which 8 ohm jack you plug in to.