Check them daily. Leaves and large debris will stop flow through the filter and make your water cloudy. In the spring or fall when leaves are falling, you may have to check it every hour.
Never put chlorine tablets in the skimmer. It breaks down the plastic and you will have to buy new baskets.
This is where the water goes back into the pool. You can usually adjust them to direct the water in the direction you want.
Usually no adjustment is necessary.
If you see bubbles coming out, that means you have a leak somewhere that is letting air into the system, and it needs to be repaired.
Know your pool tools
For more information check out our Pool School documentation: www.midwestcovers.com/services.html