Fitting ailerons is not exactly new to the EasyStar so here is my rendition.
Using 1" masking tape I laid out a strip across the entire straight part of the wing
Marked 10cm from edge of surface (the first part that can be seen when assembled not the hidden section).
Marked 40cm from that mark along.
Cut along both marks
Cut along the side of the masking tape.
Measured 5mm back from cut edge (depth of wing in cut)
Cut a diagonal section from the wing (to allow aileron movement)
Using masking tape to template the servo and its throw area (about 1cm longer than just the servo).
Used masking tape to make straight line from box section cut out.
Stuck servo template below masking tape line.
Using scapel I cut out the servo hole and a groove along the masking tape line.
The servo has two tabs so with the servo partially in I marked the foam and cut out little sections for the tabs. It goes in really snug now.
To hide the wire I cut a 5mm groove along the box section insert.
With the servo extension cable attached I positioned the connector part on the box section insert and pushed to mark it.
I then cut out that area with a scapel
Cut another groove where the wing meets the chassis for the cable to exit (and attach to the chassis All closed up and pushed together.