a) string them onto the yarn you are using before you start to knit. Put on a few extras 'just in case'
b) string them onto a thin, strong carry-along yarn and knit the two yarns together placing beads where you need them.
c) using a crochet hook, draw a loop of the working yarn through the bead, and knit the loop with the next stitch
Check a good reference book or on-line video about knitting techniques to keep the bead facing in the desired direction
Salt Spring Island