I think it’s really easy to get mixed up like that when you are new to knitting - good for you for taking a class…I played around with yarn and needles for an embarrassingly long amount of time before I got the hang of it at all and I am certainly still learning. This is an amazing forum to help you! I highly recommend sitting down with yarn and needles in front of the videos on this site - Amy’s explanations are invaluable.
The best advice I can give you is to remember that your stitches always start out on the left needle and you move them to the right needle. When all the stitches from the left needle are on the right one, then turn it (as you learn more complicated patterns, you may turn earlier but not yet) so that your newly finished row is on the left needle once again and your right needle is empty and waiting for the next row of stitches. If you find you have trouble keeping rows straight, you can get a stitch row counter which might help or simply ‘read’ the stitches of the row before. Knit stitches look like little scarves or upside down V’s and purl stitches look like little pearls or bumps.
Hope that helps a little!
If you have more questions, feel free to PM me or ask the wonderful knitters on this forum.