Can someone tell me please how to get Points? Thanks

Doing nothing.

read the FAQ

"Every time anyone submits a game, every member of the site, excluding the giveaway creator, receives 5 percent of that gifts value (in USD) in points. For example, if a $50 gift is created, every user on the site receives 2.5 points. And, if a $20 gift is created, everyone would receive 1 point. These points can then be spent on entering giveaways."

For other infos, you can check the FAQ: http://www.steamgifts.com/forum/91wob/faq-and-guidelines

Wait for it..