move your cursor exactly to the left of the list (i.e. no blue box is around it), then move *once* to the right. This places the cursor right before the first bullet in your list (the blue box is now around all of the list). In the focus bar you'll see that you are currently inside the "Itemize" tag. Now click the little wrench in the toolbar: you'll see a option to set the vertical separation between items  ("Item vsep"), which defaults to 0.5fn but you can set to e.g. 1.5fn.

Best,