The best way to do this is to create a numbering system for the sample sites in the order you’d like them to appear.
Just add a number to the start of the name of the sample.
01. Top Vine
02. Middle Vine
Make sure you prefix each number with a '0', otherwise they will end up as a jumbled list.
(You can change the name of a sample in the web app, by clicking on the sample you want to change, and clicking ‘Edit Sample’.)