Crochet: how to start a DC border?

[Pompelma]

I'm being thick again and am having a crochet brain freeze.

So I'm well on my way to making my granny squares bag, have finished joining all the squares and now just have to add a DC border to the top. The pattern I'm using just says "now just work a DC into every stitch" - but I can't figure out how I begin (slip stitch? how to do that into an existing chain? or just insert the yarn where I want it?) and then because I don't have chain to make a loop, how do I get the two loops I need on the needle to start with so I can begin my DCs?

I can't find any tutorial or anything to explain it, and any I've seen about adding borders assume you already know what you're doing and go so fast I can't see what's going on clearly enough.

Sorry if I sounds really thick! Thought I could work it out by myself but I just can't!

Join the yarn into a stitch (any stitch will do as presumably you will be going all the way around the top) and then chain 1. That will start you off at the right height, DC into the same stitch and then DC into every stitch until you're back where you started and join into the first DC to finish.

Thank you TimTam! I've finally got it now. Don't know why I just get so muddled sometimes at the start but once I get going I'm fine.

Good. It's tough when you're starting, but it gets easier really quickly IME.

You can do it by putting the slip knot on your hook as if you were starting and just making a DC in the first stitch.