Practice, practice & practice - start with 10 or 20 stitches & knit every day at a dedicated hour without any distractions (tv, telephone,family) until you get the technique "in your hands". This means knitting by ROTE. This may take days or weeks. When you master the knit stitch, then do the purl stitch in the same manner.
Art & science work together - the brain will tell you when you are ready to move on. My experience as a tutor helped others to learn successfully just by practicing.