Briarine, The knit stitch is like the slip stitch in crochet, except you are putting the needle over the yarn (scooping it with the needle) instead of the yarn over the hook before pulling it through the loop.
Did you friend teach you holding the working yarn in your left hand like you do in crochet (Continental) or holding the working yarn in your right hand (English)?
Your latest top is beautiful! I love the colors and the pattern The nylon in the yarn content will help the alpaca keep its shape and not get longer and longer. I love spinning and knitting/crocheting with alpaca but it doesn't have the memory of wool. I like to combine another fiber with alpaca, usually a fine wool, to help with that.