Provisional Cast-On

Here is a question regarding doing a provisional cast on. :

The pattern states: With crochet hook and scrap yarn, chain 26. With 1 dpn, pick up and k 24 through the sts of the back of the chain. Do not join. Knit one row. Next row Purl. Carefully remove scrap yarn, placing open sts on 2nd dpn. Rnd 1 With free dpn, pm for beg of rd, and k 12 of the new sts; cont around, distributing sts evenly on 4 dpn-48 sts.

I am totally confused with this. I consider myself an intermediate knitter, but I have never come across this before. I don’t understand how they are ending up with 48 stitches. I think I am going off track when they are picking up stitches on the back of the chain.

Here is my answer:
Make sure that the scrap yarn you are using is a completely different color then the yarn you will be knitting with. So if you are knitting with black yarn, I suggest you use white yarn as your scrap yarn. Having a sharp color contrast between the two makes it easier to see what you are doing.

The scrap yarn acts as a holder for your ‘live’ stitches’, that you will create. After you’ve picked up and knit 24 stitches on the crochet chain, knit one row and then purl the next row. Leave those stitches on your double-pointed needle. 

Now, with another double-pointed needle,  you will then remove this scrap yarn, making sure to pick up each little ‘hump’ created by your knitting yarn. You are basically taking each stitch off the scrap yarn and placing them on your knitting needle. You picked up 24 stitches to start with, so with the other needle you will have the same 24 stitches taken from the opposite end, thus equaling 48 stitches.

Now take these 48 stitches and divide them equally among all four double-pointed needles. (12 stitches on each needle.)
Here is a video that shows exactly how to do this: