Reps and nominations?

My apologies if I've posted this in the wrong place. Move to where ever best suited by the powers here that be

Can someone point me in the direction of where I can learn more about what Reps and nominations are? I've used the reps and I'm wondering how the amount is increased? I've been giving the highest number allowed me...I think..but it's tiny compared to the generosity of others. Is there I way to increase that amount? (I haven't given a negative and am having trouble even imagining using them lol) Also, some have been very generous with their reps. Is there a way to thank them like the "Thank" at the bottom of a posting? And what does being nominated for something mean, what is it for, how does one go about it and is there a way to thank for that too? This is only the 2nd forum I have been on EVER so if this is all elementary I'm very sorry Could someone please humor me?

Thanks in advance!