Hi there. Welcome.
It sounds as though you've found out the basics, and gone a way past that. If you've painted your models, get them in the Gallery. We want to see what you've been up to
40k (and Kill Team) can be difficulty to get into, and we get lots of questions about how to get started, how to expand. Leviathan is a great start, and not only for playing Space Marines or Tyranids.
Ask away, post up, and have fun