Ok. So, you spawn on this barren land surrounded by these green shits. There are no ores, just bedrock. But there is hope, and it might be quite obvious to some.
Finding wood, getting coal:
On these barren plains are NPC villages. They still spawn in Superflat. To get wood, just steal some off the farm or house trims. Then, when you get enough stone (make a wooden pick) then mine a lot of cobblestone. Then craft a Furnace, and burn logs into Charcoal.
Getting some food:
It's quite easy. Just harvest some wheat from the NPC farms, or find them in chest.
Finding some stuff:
In every NPC village, there might be a chest. Chest are in Blacksmiths. Inside a chest (this is all I know) is:
Getting these can bring you to the Nether. You can get lots of materials to settle in the Overworld safely. Make a nice netherack base (or netherack brick, whatever you want) and make a tree farm and flourish. Getting water is from wells in NPC villages. This might not be the best guide, but I made it. Hope you enjoyed!
Looking for challenges? Some are listed on page 2!