My sister got a similar bracelet to this for her birthday, I really liked it, but instead of buying one for myself (they're fairly pricey!) I thought I'd attempt making one instead. It turned out great! And pretty easy...
Firstly, measure out your leather cord so that it can wrap around your wrist twice and with some extra length for tying it shut afterwards (i recommend around 7cm - you can always trim it afterwards). Then fold the cord in half and use the elastic to tie it together so that you get a little loop at the end.
If your elastic is thin enough to go through your beads twice, then you can use it for the threading. Mine wasn't so I tied some cotton thread on the end.
This is when it gets a little complicated, To thread the beads, you need to go over the top leather cord and then through the space in between them and then thread your bead,
Then push your bead up into place and take the thread around the bottom cord and back through your bead. Then over the top cord again.
Keep beading like this until you are left with around 7cm of cord 'un-beaded' (or enough to knot the thread and then tie the cord)
Then wrap your thread around your cord like you did it step 1 and tie it tightly. You can then knot the cord so that it will slip into the loop at the other end of the bracelet to secure it around your wrist.
Tah-Dah! A beautiful new bracelet that your friends won't believe you made yourself!