It is recommended to get the Horse first before proceeding Get a Horse southwest of Lookout Landing
Exit Lookout Landing Skyview Tower and proceed west
Go left at the first and second fork. At the second fork, going left is recommended to avoid the Battle Talus.
Take a left before the forest lodge, then the next right Follow the road up the mountain
Go north up the mountain and enter Goron City
Go through the center of Goron City Turn left in front of the large building at the back and follow the road up the mountain
Go down the narrow hill to the left of Mine Cart YunoboCo HQ is on the hill with the high ground in front of you (You can use the Mine Cart)
How To Get There Using The Mine Cart
After leaving Goron City, you can reach YunoboCo HQ at once by using a Mine Cart. Attach a Fan to the Mine Cart on the right side with Ultrahand, and put them on the rail to move. However, it is not a significant shortcut, so you can walk towards it normally.
What To Do At YunoboCo HQ
Buy Flamebreaker Armor
The Flamebreaker Armor is available at the YunoboCo HQ. Equip any one of the three Flamebreaker Armors to guard against flames. The Head Armor costs 1400 Rupees and the Leg Armor costs 1200 Rupees, so it's recommended to buy the Body Armor for 700 Rupees.