Tuner help please

Hello friends.
I write to you all in need of help. Last year I was given a dulcimer by a friend who thought that I would play it more than her. I resolved to do just that in 2025 and today I was trying to tune it up and one of the tuners came apart. I got it back together once, but then...it came apart again.

So, I was wondering:

1 - how do these things work?

2 - are there more modern versions that make them easier tune? (I like the way they look)

3 - should I get guitar tuners instead, could I even install them on this type of dulcimer?

4 - Any thoughts, guidance, or helpful advice would be much appreciated! 

Thanks a lot,

Sal