Next step? Knitting a baby hat

I just started knitting not long ago and have found it challenging to say the least. I am currently trying to knit a baby’s hat and I’ve gotten as far as binding the two pieces. But now I need to know how to join the two pieces together on the 3 sides. Can anyone help me out.

I think mattress stitch is what you’ll need to do. Scroll about halfway down the page to finishing techniques and you’ll see how to do it.

Mattress Stitch

Here’s another one.
Knitty -seaming