I moved this so more people would see your question.
To join in the round, have the stitch with your yarn on it at the point in your right hand, and the other end stitch on the point in your left hand. Then knit from the left to the right.
Ingrid is right, but I’d like to add that you should be careful to make sure your knitting isn’t twisted before you begin the first stitch that joins. The way I do this is to look the stitches over carefully and be sure that the cast on edge of all the stitches is on the inside edge of the circle of the circular needle as I am holding it, ready to join.
The most basic way to “join” is just to start knitting, but there are other ideas out there about ways to join in the round. If you’d like to explore some of the other ideas you might find them with a search like “circular join”. Good luck.
[FONT=Comic Sans MS][SIZE=3][COLOR=darkorchid]I generally knit a couple of rows flat and then join. Much easier when there is something to “hold on to”, less chance of twisting and the first rows are a bit looser and longer than the CO which makes it a bit longer and easier to work with. [/COLOR][/SIZE][/FONT]
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[FONT=Comic Sans MS][SIZE=3][COLOR=#9932cc]Ask 6 knitters how to do something and you’ll get at least 10 answers! And they are all right![/COLOR][/SIZE][/FONT]
The working yarn will be in your right hand so when you go through the loop on the left needle it will join. Pull that first stitch kind of tight that first row or two and if it’s not perfect (it rarely is) you can fix it with the tail yarn when you weave it in.
NOTE: Make sure your stitches aren’t twisted on the needle before joining. There is no fix for this, you’d have to start over.
When I need to join in the round, I make sure that all my stitches are facing either in or out. If I have a few stitches (like for socks) they point in and if I have a bunch of stitches (like for a sweater or bag) I have the point out. It’s easier to do a visual inspection to make sure there isn’t a twist in the stitches. I usually go through them once by hand turning them all in (or out) and then just start knitting through the first stitch I cast on.