How long to joint compounds have to sit to dry?

As stated it depends on brand and type, Premix normally 12 hours, No powder type as fast as 5 minutes, Although I would not suggest you try 5 minute try 45 minute mud. Then it depends on temperature humidity air movement etc. It will dry faster but you have to work faster as well.

It does not have to be totally dry to start the next phase but if you touch it and it sticks to your finger it is to wet to apply another coat which you will now be using Topping Compound-

Here is a way to speed up dry time put a fan right next to it(called forced air) this will force the moister or water out of the compound and make it dry faster.

Perry Tradesman

The time it takes for the joint compounds to dry depends on brand that your using. Generally 12 hours is enough, I like to let it dry over night.