Sewing pants, beanies ect.

I just remembered I have a seeing machine that has been collecting dust. With this I recently have tried teaching myself to sew. I started with a beanie but my machine keeps getting tangled or even when it doesnt tangle the fabrics dont hold together with the string. I have watched many videos and still dont know whats wrong. Someone please give me tips or something. I would love to learn how to sew ski pants before the end of summer.