I recently learned to knit. I almost gave up as the lady who showed me only showed me how to make the stitch. She didn't mention anything about how to hold the yarn. I practiced for hours ready to give up before I realized maybe if I hold the yarn and the stitches both it might be better. I did that and it seemed to help. I finally stumbled upon this site and learned how to hold the yarn so that securing my stitch with fingers was no longer necessary.
Then I had another problem. I was taught like you, to knit through the back loop. I didn't want a problem with patterns so I then learned to knit English at first. I had a heck of a time because the cast on method I was shown by my friend worked well with knit tbl but not with English style. I finally reviewed the videos and learned the long tail cast on and that seemed to hold the cast on stitches tightly enough to knit English style. Now I learned Continental Style as well and several kinds of methods to purl. I am so glad I didn't give up. I also learned that different methods for me work better for different patterns and different yarn. Eg. I found Norwegian purling works well with wool and especially with mercerized wool but it is terrible when working with cotton yarn. I also like to do English Style on a row when I am using a cable needle as I can manipulate the needles easier. Don't give up. Try maybe knitting a pair of simple slippers with cheap acrylic yarn or wool. I did several pairs of these practicing the various stitches.
. This is a simple pattern. A lot of people seem to like it. The slippers knit up fast and there is nothing fancy to fool with. Perfect for practice and you get comfortable slippers as a result