How do I secure a lining to the inside of a bag:

I am knitting another lunch bag by double stranding Sugar and Cream and 1 strand of Red :heart: together. The first one I made is almost like a big loose sack… This time I want to add the inside pockets of a set of bluejeans. I saw several people last summer do this to the booga bag and that way they had pockets in the purse. Is there a way I can add some inside pockets to my bag so I could utensils or sodas? Right now everything ends up in the bottom of the bag?
thanks if you can help~!

Here’s a link to how to line a bag. You could probably just sew the pockets onto the sides.