So, I have a nice new half stack for my birth day (today). And It talks about "Ohms". Like it says it has 8 Ohms but a minimum of 4 Ohms. What are ohms, and how can I use them.

And then, I have a multifx processor on my pedal board, how do I utilize the effects loops. I only use my processor for effects (chorus, flange etc.)
Match the ohms from your cab with the ohms from you amp. Ohms are units of electrical impedance. Match them up or you could blow out your output transformer.

For the effects loop, look on the back of your amp most likely. It should say effects loop send, or preamp out. There should be another one saying effects loop return, or power amp in. It should go effects loop send -> effects -> effects loop return. Look in your manual it should have all this.

What amp did you get?
The Ohms stuff would be referring to the impedance of the speaker and i dont think there is much you can do with it. I think that the speaker will operate more efficiently at the lower impedance but i dont know how you go about utilizing that.
thank you all....I have 2 Ohm Inputs, both 8 Ohm, on my cab it has a 16 and a 4 input.

And I got the Ibanez TBX 150H