Controls: WASD left-click right-click tab space 

1. Flint Tools

Run around and collect bushes, black rocks (flint), and very tall green plants (papyrus, which is by the water.) Craft the Flint Pickaxe & Flint Axe. Plant papyrus (needs water. do it or you'll need to wait later), cut trees (you need lots of wood), and mine rocks (you need both flint and stone). Farm papyrus, build a workbench & furnace & oven (you get more crafting recipes beside said buildings). You'll need food, so build a Flint Sword & Shovel. Kill cows & cut grass for wheat seeds (to plant wheat seeds, right click on grass with the shovel & then right click with seeds)

You're probably having inventory problems, so besides replanting all your seeds, papyrus, saplings, and flowers, you can also stick your items in the cooking slots of the furnace and oven for more inventory space. 

2. Farming

You need to farm papyrus, wheat, and trees (saplings). Papyrus and wheat both need to be planted beside water. For papyrus and wheat, you can hold down left and right click while holding papyrus/seeds to collect & replant crops at the same time. 

3. Furnace & Oven

Use the Furnace and Oven as shown. [If the images aren't showing: in the furnace, there's a fuel slot & 3 item slots for smelting. For the oven, there's a fuel slot. Use one and only one of the four slots to cook.] For the furnace, you should ensure that the items smelting are of the same stack size. For the oven, do not try to use more than one smelting slot at a time. Add the fuel in last. They will both burn fuel even if there is nothing to cook, so never add more fuel than necessary. 2 planks can smelt 1 item, 1 log smelts 1 item. Maybe I should've used coal... (the rocks in the bottom floor of the map contain the most coal) 

3. Cave

Assuming you're well fed, build a loom, and take just enough papyrus for you to make a rope. Get a few stone walls, and don't use wooden ones since you probably need the wood. Use coal and sticks to make torches. Place the rope on one of the holes in the ground, and descend, sword and pickaxe in hand. Collect iron and kill or fence off enemies with your walls. Skeletons are dangerous, zombies are not. Get iron tools and armor as you go down to the bottom of the map. 

4. Last Cave

In this area, you'll need to kill a bunch of demons until you find the Death Crown Scroll, which you need to use to gain the recipe to make the Death Crown. Some enemies, I got mine from a zombie- drop a Death Stone. Get gold ingots and this stone to craft the Death Crown, which - don't wear it - can be placed on a black pedestal in some black structure on the surface to spawn the final boss of the game. Anyhow, get ready to get spawnkilled a bunch by this boss. 

Tips

Use coal to smelt. Consequently this means you'll be using stone walls instead of wood walls. Use both a lot, since your weapons are weak. 

Never ever make leather armor. Cows seem to be finite, backpack first. 

When fighting the final boss, ensure your inventory has only weapons. Since you'll probably die a lot. 

When farming, while holding your seeds, hold left and right click to harvest & replant simultaneously.