How do I use circular needles? I’m trying to make a blanket and the stitches all just end up connecting and i make a big circle!

Don’t connect them. After you cast on, turn the needle like you do a straight needle and work back over the sts. At the end of the row, turn again and do another row.

To join the yarn is coming from the right needle so make sure it’s coming from the left needle just like when you knit with straights.

The way I think of it is to consider each end of the circular like it was a straight needle. After the cast on row you do have the working yarn attached to the left hand needle before you do the first stitch. Of course when you knit the first stitch the yarn will now be attached to the right hand needle tip. At the end of the first row of knitting put the needle tip that is in your right hand into your left hand and the one that was in your left hand in your right hand. Then you start the next row just like you would on straights.