Burn in is pretty rare but can happen under the right circumstances. The keys for success in avoiding it are:
1) For the first few hundred hours I suggest making sure you vary your content and stick to full screen programming and run the OLED Light at a low setting, say at like 50. Even though I have no scientific data to back this up Ive always done this with my emmissive displays and have never had burn in issues. Try to limit gaming early on in the TVs life and stay off of channels with bright, obnoxious logos at first. Make sure to power the TV off at night so it will run its comp cycles.
2) After the first few weeks you are basically good to go. There is no reason to run the OLED Light setting at 100. 50-75 will cover most viewing conditions. Contrast can be set at around 85 - 88 an Brightness ends up good for most people at 50-53. Use Expert Day and Expert Night modes for base settings and tweak from there. Post back and we can help with some base settings for you.
3) You can game quite a bit but after a gaming session Id run the TV for a while with some full screen content just for kicks. Cant hurt. You can watch anything you want and any channe you want but be mindful of channels with those bright logos like CNN or MSNBC. Honestly, running the TV on news channels a lot is a bad use case for OLED, IMO. Its lame that some channels insist on leaving their stupid logo on the screen the whole time but thankfully, most channels have got the memo and dont do that. Its either trasnparent or it goes away after a few mins.
4) Dont overthink this! Most people have never and will never have a burn in problem. If you game like 18 hours a day or leave the TV on some news channels for several hours a day - Id buy something else. Otherwise, enjoy the awesome PQ.
Hope that helps.