Should I root? If so how?

Hey, I'm a total Android noob after fancying a change from IOS but the model I'll be going for will only have 16GB which aint much for me so I'm wondering if I can move my apps (mainly game ones I'm thinking of e.g. GTA etc. to the MicroSD card I'll get on the Ascend Mate 7 however it is my understanding that I need to root the device to do it.

First off, what is rooting? How do I do it without screwing up and can it be done with a MacBook?

Thanks, Eilidh