The trick is that when you've joined properly, (a) you're still going the same way, and (b) the last cast-on stitch is right next to the first one -- like any other two knit stitches in the whole thing.
What cast-on method are you using? That might make it look funny (or be easier or harder to do it without a twist).
Well, first you need either a circular knitting needle (meaning two points and a cord between them) of the right size for the item you're trying to knit, or a set of double-pointed needles (they come in packages of either 4 or 5, depending on brand).
When you cast on however many stitches, you then instead of going back and making a flat piece, knit the first stitch you cast on right after finishing the last stitch, which makes a loop. Be sure not to twist it -- man, I did that a lot when I got started -- unless that's what you MEANT to do, like for a Moebius scarf or something. But mostly, don't twist.
If you're using a circular needle, that's it -- mark where you started with either a stitch marker on the needle or a safety-pin style marker pinned into the work, so you can count your rounds. If you're using double-points (often abbreviated DPNs), you have to distribute your stitches onto several needles so they can make a box or triangle shape while you're going around. Always make sure to leave one needle of your set free -- that's the one you're knitting 'onto'. When you fill it (and empty one of the previous ones), rotate the work and the new empty needle is your 'working needle'.
Was that at all clear? I could probably find you some tutorial videos on youtube if you're having trouble visualising ...
Join Circle of Moms
Sign up for Circle of Moms and be a part of this community! Membership is just one click away.Join Circle of Moms