Cloth diapers

Can anyone who does modern cloth diapering clear my doubt?

If u are using these diapers- whether it’s prefold with a diaper shell, or inserts with a diaper cover, HoW do u know when the kid needs to be changed? How do you know when they diaper is wet?? Pls enlighten!

Do u just do every two hour changes or do you have to touch inside n check for wetness??? How to tell?