Saving a bookingID from a website so I can reuse it in another section

The issue is @lisa.s is looking for the best, which to me is relative. Anyway, the below is a way that will work but being the best is for you to decide. Are you able to handle the Script tab or are you limited to the Manual tab?

If you are only going to get the bookingID once for all time, maybe just type it into a spreadsheet yourself manually.

Edit: if you are limited to just the Manual tab, then create a new Test Case and copy and paste the code from the link into the Script tab of the new Test Case. After that, look at the Manual tab and duplicate it into your TC.