It's very easy to add some decorative features while you are knitting.

When you reach an area that needs a bead, slip the stitch off the needle, push a crochet hook through the hole on your bead and catch the stitch to pull through the bead and replace onto your needle. You may find that the bead is large and it is too tight to pull the stitch through, In that case, you can either: 

1. Knit with a looser tension a few rows before and after the bead

2. Undo the stitch before and after the spot where the bead is to go, take the stitch from the row below that is now on your needle and move it to the next adjacent needle. Now you have a longer loop to work with. Pull that through your bead and continue knitting

3. Enlarge the stitch size on the needle that will get the bead as well as each needle on either side, by pulling each needle down to the out-of-work position from the carriage side, one at a time to pull the extra slack across the needle bed until you reach the three stitches where you want to place the bead

If you are adding a button, do the same kind of thing as above but pull the stitch with your crochet hook through the buttonholes. You can also buy decorative holiday tokens such as the small bell that was added in the picture.