When your needle gets fulll? Not understanding this...
When you knit on straight needles, you are working in rows... when you get to the end of your row, you turn your knitting so that you can purl back, or knit back if you are doing garter stitch, or whatever the pattern tells you.
Are you knitting circular?
Did you have a look at some of the videos here? They are great and really helpful. You can learn just about anything from them.
I think you will enjoy knitting very much.
Perhaps, because you are just beginning, you might try to find other knitters in your area; anyone would be willing to knit with you. Knitting in a group is a great deal of fun.