How to get better at BJJ?!?

I just started BJJ last week. I SUCK! Everytime I go to the dojo everyone owns me. I am kinda just thrown in which I guess is the best way to learn. But I feel SO lost! I know all the positions and I know which ones are more advantageous. But, I am unaware of the means by which to GET into those advantageous positions. What do i do, just hang in there and with time and practice it comes? Or should I get private training which costs a load? Or watch certain videos online to get a better understanding? PLEASE HELP!