you have to wait for your giveaways to end and then you will level up based on the price of the games

Kill things, get EXP.

.....Oh, not that kind of level up.

Create giveaways and once they end you may or may not level up based on the CV of the games you gave away. If a game was bundled you get reduced CV, if it was free you most likely will get no CV.

Cool, you actually made giveaways, and not for games that were given away for free (those worth 0 towards next level) - as others said, just wait a bit :) your giveaways need to end, and to get feedback that the winners acticated their wins.q

The answers to your questions can be found on the FAQ.
I recommend taking a few minutes to review the Contributor Value and Levels section. It can be a little confusing initially, but that should mostly cover everything you need to know.

Do quests, kill mobs.

You read the sacred documents. First you have to pledge to offer your first born to the SG gods, but then it is pretty straightforward.