HVAC lights & screw size

i have uploaded 2 pictures so you guys exactly know what i am talking about
first picture is the front of Climate AC Heater Control when i press any of the 3 buttons (marked them by red arrow) the green light light inside the small window lights up. but none of the 3 symbols are illuminated does anybody know if there is a bulb there? as i have already replaced the 2 bulbs that lights up the hvac

this is the second picture, over here i am looking for screws does anybody knows what size is the screw also in the picture you can see the two bulbs behind, those two bulbs are already replaced but 3 symbols still do not light up
To tell the truth, I never made anything such by myself, and I admire people who understand this. Honestly, in a similar situation, I usually adress to a specialist or service. Indeed, I think that everything that is linked with the techniques better not to touch and left to the professionals. I have a friend, he is working in HVAC. Some years ago he was studying at https://www.hvacschools411.com/school-cost/. He told us many ridiculous stories related to his work. So, I learned from him the one thing that if you don’t know anything, then it’s better don't poke your nose there at all.