Is this for the top of a hat? That’s typically where you’ll see instructions like that. You can get a yarn needle to pull the stitches through. It makes it easier. You’ll see why you do it when you’re done. When it says “secure”, generally, you just weave in the end to the non-public side of the knitting.
When they say to pull the stitches through they just mean that you need to thread your yarn needle, which you already know, leave your stitches where they are on the needle and take the yarn needle and [B]feed [/B]it through the loops(stitches) on your knitting needle. Do a few at a time cause you can’t get the yarn needle through all at 1 time. It’ just like doing a “lifeline” which is shown on a video on this website. This is the link for the video http://www.knittinghelp.com/videos/knitting-tips