Congratulations on your conversion. You're going to be so glad that you took the time to do this. When you get ready to change out your sand, drain the filter and then use a shop vac to suck the old sand out. When you refill the filter with clean sand, partially fill the filter with water before adding any sand -- maybe 1/4 full of water. This helps to protect the laterals and inside piping inside your filter and also allows the sand to be distributed more evenly. Then, as you add your 200# of sand (or whatever amount your filter calls for), the water may come out the top of the filter to allow you to add the full amount of needed sand.

One other note I might mention here for some of our new members who may not know this. It is not necessary to replace your sand every year like some pool stores will encourage you to do. I am on my 11th season with the same sand and I think my fellow mod Poconos is on his 13th year with his. I also think CarlD has had his same sand for awhile but I don't know how long. Just an FYI.

Edit: OOPS! I forgot to answer your question about CYA levels. 30 is a good initial level to shoot for. If you find that you are having trouble making it through a hot sunny day without losing all your chlorine, you may decide to bump it up just a little more. But, wait and see before making that decision. It is always easy to add more CYA but no good way to remove it other than doing a partial drain and refill.