Hey tricktag, I'm really sorry to hear about your stuff getting destroyed in survival. That is not okay and should not be happening. The first thing you should do when that happens is submit a modreq (/modreq [message]) stating that you have been griefed, and don't fix anything (the UA or staff that helps you needs to see what was done). They will come and find out who did it. Next, once that is sorted, is claiming. To claim you need to use a golden shovel ($20 at buymore, or just ask around, people are usually more than happy to help out and give you one if you don't have the $20). Holding the shovel you right click on one corner of the area you want to claim, then walk over to the other corner and right click again (holding the golden shovel the whole time, don't switch what you are holding until you are done). This will either tell you that you have claimed the area, tell you that you don't have enough claimblocks for a claim that size, or tell you that the claim is too small (the smallest you can make a claim is 10x10). Once you get the claim created the only people who will be able to access it are ones that you give permission to. I hoped this all helped. If not, just ask in-game how to claim your area and if a UA or mod is on they will help you.
You can claim them by buying or crafting a golden shovel right click in one corner and the other corner so u can make it rectangular but if u dont have enough block u should buy blocks or play for a long time. i wish this helped :shovelgold: