How to level up on this website

https://www.steamgifts.com/about/faq under Contributor Value and Levels

The simple answer: Make giveaways. They give so-called CV, and you will gain levels.

The longer answer: Make giveaways for full priced games. Games that have been bundled give limited CV, and games given away for free give 0 CV. It is the date of the first bundling/or free giveaway that counts, meaning; If you give away a game today that was bundled yesterday for the first time, you will get reduced CV, but if you give away a game today that becomes bundled tomorrow for the first time, you will still get full CV for it.
These CV reductions does not, however, take place in real time. They are often batch-applied retroactively (due to low number of staff/low number of volunteers), sometimes a rather long time afterwards, so the system isn't perfect. But it is the system we got.

As you gain levels they become consecutively harder and harder to attain, but to rush up a few levels in the beginning shouldn't be too hard. Read the FAQ and the guidelines for more info on CV and the site in general.

Good luck, and welcome to SG.