Click to enlarge.

Here you can see the hint for making combos.
We can see from what position we can go to the next one.
Why is this so important?
Because it can prevent you from making “dead” dombo parts like F B .

Take a look.

Here we can see the explanation for the combo for
UNLOCK shown on YT movies. [see in older YT related posts]

Shown on the Gesture map,

starting from R (1) we can choose between F,D,T or B.
Our choice is B (2) then L (3) and finally F (4)

So simple