OK: In that box, if the four whites are tied together, they're neutrals.
The black common to all three switches is incoming power.
The other three blacks are switched power to the three lighting runs you mention.
Before you disconnect anything, make a diagram or mark the wires so
you keep track of 'who's who'.
Now look at the instruction sheet for those timers.
The white will be 'neutral'.
Im guessing here but I'd say that black and red are 'power in' and 'switched line out'
respectively, but it might be the other way round.
(Because the timer needs power to drive the 'clock', it does make a difference.)
If there's no bare ground in the box, and it's metal, get 'ground clips'
(little brass clips that grab the box edge with green 'pigtail wires to the device),
and ground your timers to the box.
Retired Electrical Consultant