Learn what to do at the start of a new game of Breath of the Wild.
Open Your Eyes
After a cutscene, you will automatically get up. You can press + to open the menu, where you can save, change your options, look at the controls, and so on.
Check the glowing blue panel. You will get a Sheikah Slate, and the door will open. Go through, and open the two chests to get a shirt and trousers. Press + to go into your inventory and equip the shirt and trousers.
Go farther, and check on the glowing panel to open the door. Go farther and push against (or jump onto) the rock wall to climb it. Link can climb almost all surfaces, so try it if you get stuck. You can press X to jump more quickly up the wall, but be aware that this uses more stamina than normal climbing.
Go outside. After the cutscene, you will see a tree branch on the ground nearby. Pick it up. It will automatically be equipped as a weapon. There are also some more tree branches to the left of where you were standing during the last cutscene.
When you are holding a weapon, press B to put it away. You can find better weapons by fighting monsters or opening treasure chests. Weapons and other equipment become damaged with use, and they will eventually break, so you should pick up as many weapons and other equipment as you can.
Feel free to climb trees and walls, where there might be more items to pick up. Just be careful not to climb too far up; if you run out of stamina while climbing, you will fall.
Go to the old man. You can take the apple by his campfire, as well as the other items nearby. Talk to the old man. Ask who he is, then ask where you are. He will point out the temple in the distance.
If you go in that direction, feel free to take the Woodcutter's Axe. It can be used as a weapon, but it is heavy and slow. It can also be used to chop down trees, and you can hit the tree trunk to turn it into wood. If you have a source of fire, you can turn the wood into a camp fire.
Eventually, a voice asks you to go to the destination marked on your Sheikah Slate, so press Select to look at the map and the destination marked on it.