By placing the access point centrally and arranging the extenders in a spherical pattern. For example, AP in the centre of the ground floor, extenders at the front and back of the ground floor, and the same on the upper and lower floors. Simply so that each EX has approximately the same distance to the AP.
It would be wrong to place the AP in the basement and then the EX in the ground floor and first floor.
The EXs show the reception strength of the AP by means of LEDs. In this way, the AP and EX can be positioned optimally.