These products are mostly used after the hair is dry, but can also be used on wet hair to help speed up drying. If you're using it on wet hair, apply it as your last product that goes on before you start to dry it.
Hairsprays: If you're using it to spray on hair that's already dried, you can also use it to break your cast. Spray onto one side of the head while leaning over, then quickly set the bottle down and scrunch to break your cast AS you scrunch your curls to set them a little curlier and with volume.
Pomades: These products you can use wet if you like, but normally I use them on dry hair.
You can also apply the hairspray to your finger tips and massage into the scalp in areas where you'd like to see volume.
To reduce frizz on days where you are not washing your hair, spray over your hair and then pet your frizz downwards to lay it down.
Remember, too much hairspray can leave your hair feeling sticky which may reduce the amount of days you can go before washing, so play around to find the right amount to use for YOUR hair. Everyone is different.
Read the product descriptions for more info on how to use each one.