For stairs you first need a stairs kit. There are 2 types of stair kits, a Stone Stairs Kit or a Wooden Stairs Kit. A stone stair kit is made by adding Two Shafts to Cut Stones, and wooden ones by adding Two Shafts to Boards. In order to make a Wood Stair Kit add Boards to Two Shafts. Now, place them on floor stakes for your stairs. But, in order to let them face in the right direction, look in the direction you want to place it when placing it. For example, of you place a stair kit on floor stakes when facing north, the stair faces north. If you do this wrong, you can always remove it with a mallet. If you want to walk up the stairs, just walk on it. To make a second layer for your house or whatever you are building, look at ‘Roofs’.
Buildings in YAH don’t have roofs yet. And it would be more realistic to add roofs. You make roofs by combining cut stones, boards, flat stones or any other materials that are needed for floars (appart from bricks) to a wall. For example, if you do this with a wall facing to the north, a roof apears on the south of the wall. But if you would have these roofs it wil block your sight so the roof disapears if you go inside the building. If you put a roof on the wall again, another roof apears on the south of the roof there allready was. Its hard to explain, but it works, and i think this is the best way to make layers to a building.
There are different types of furniture, but to make some furniture you first need nails. They are made by makeing a steel mallet, which is made by putting 2 hot wrought irons on a flat rock. Then use a smithing hammer for hot iron plate. Now, make a fake nail by adding a steel chisel to a wrought iron and hit it with a smithing hammer for a wrought iron with iron bit. Now grab the iron bit. If you do this, nothing changes to the wrought iron, which can be used again. Now hit the iron but with a smithing hammer for a fake nail. Put the fake nail on the iron plate and hit it with a smithing hammer for the nail mallet. Now, to make nails, put a hot steel ingot in a bowl and pour it in the mallet. Now, if it cooled down, use a bowl to get the nails. Now you can make different types of furniture. Not all need nails. To make a stool, use a bow saw on a straight shaft for 2 half shafts. Put these on boards for a partial stool. Put 2 half shafts in again for a stool. Add boards for a chair. Sit on it by clicking on it when standing next to it and go off the chair/stool by swiping out. You can move it by swiping towards you. A table is made by adding 2 half shafts to 2 boards and then add another 2 half shafts.
I hope this gets added, furniture and roofs would be a good idea. If someone sees a mistake or just wants to say an idea, just say it.