Make swatches!! You will have a tail unless you use Amy's fav cast on method. I'm pretty sure you can knit part of the tail into your work and then cut it, but I would work on the other parts first.
I practiced all of Amy's cast on methods to see which one I liked. Then I tried knitting onto each cast on method to further develop my preferences of which one was easiest to knit from and also which one looked good. I also tried continental and english knitting styles. I preferred continental.
When I felt confident about casting on and knitting, then I worked on purling. After that, I made swatches using stockinette, garter, ribbing and moss stitch. Then I made a hat.
We've all been there and have started up our own way. No one was "retarded" about it and neither are you. It will come. Try everything and find which ones you like best.