This may be a daft question but....
Hi Lisa,
With that type of chip you usually get a couple of ties to help you attach them. Having said that, I recently did a race where they didn't give us the ties, so I had to tie a new lace around my ankle. The chip has a couple of holes in for you to pass the lace through.
Why not contact the race organisers, they would be the best people to tell you.
They should send instructions with the chip, too.
Some I've used lately have been on a velcro strap that you put round your ankle.
The ties are akin to those that you use to tie up sandwich bags with - very easy to use