Replacement of the sand is easy but there are a couple of things you want to do first.
Make sure you have a good shop-vac, get gloves, and purchase the proper sand.
This sand filter calls for #20 silica filter sand. (this will be available online, at your pool store, or at any water treatment facility).
Here is the link for this filters manual, and for the brochure (which has good pictures)
The manual has step by step instructions on filling and starting the filter.
The only part it doesnt tell you about is how to empty the old filter media.
To start this:
1. turn off circulation pump
2. Bleed any pressure or vacuum from the system using the bleeder valve, or just rotate the multi-port valve.
3. Open the drain valve at the bottom of the filter if there is one (some dont have one)
4. remove the collar between the multiport valve, and the tank. (this should be 2 phillips head screws)
5.Remove the multi-port valve.
you now have access to the sand.
6. Remove sand by whatever means (either a scoop or a good shop-vac with a thick hose)
be sure to be carefull once you get 2/3 of the way down the inside of the tank. There are LATERALS down there that are most likely brittle from chlorine.
Once sand is removed check and clean the laterals at the bottom of the tank.
Clean and flush the filter body and follow the directions in the manual to fill and start-up the filter.
If this helped, please vote positively for me.