This could be answered 1000 different ways and I don’t think any of them would be wrong…
I would say you can normally find a closed hat on the off beat of most songs but its not like its right or wrong
I would describe a closed hat as more of a quick ting while an open hat depending on the sample could have a long ride or be short but normally some sort of crash at the beginning
Effects wise its the normal culprits (depending on which style of music your trying to make) probably a compressor followed by an EQ emphasizing the higher frequencies and then another compressor side chained to the kick maybe a simple delay or something if you’re really trying to get fancy but honestly like I said before nothings right or wrong
The closed hihats are typically shorter tailed then the open hihats. That’s why the name closed.
Open hats are mostly placed off-beat.
What I tend to do is get them off the grid a bit. This makes the groove less stiff.
Concerning the volume on the different elements:
I start off with the closed hihats. There’s often a longer tailed closed hat off beat.
As you can see in the above picture (variation on pic 1) there are 2 additional hats placed. One on 1.2.2 and one on 1.3.4. They are typically less loud and increase the idea of the groove.
Here you can see that all 6 different closed hats have different Decay, Pan and Volume settings. This to increase the room. I also use a send/return for Reverb.