Building is one of the main features that sets Fortnite Battle Royale apart from its closest competition called PlayerUnknown’s Battlegrounds. The ability to construct ramps, walls, and complex structures in just a second makes it possible to quickly hide from enemy fire or earn a height advantage over the opponents. It is really important skill if you want to master the game, but with no official tutorial, it is one you will need to learn for yourself.
Before you are able to build anything, you will have to collect some materials. Fortunately, almost everything that you see in Fortnite Battle Royale is able to be mined for building blocks using the pickaxe you get at the beginning of each game. you can try to chopping up trees or sheds for wood, that is the quickest to build with but breaks easily. Aside from that, you are also able to mine bricks from buildings and metal from the cars scattered across the map, both of which are more durable materials but slower for building.
The most important thing to take a note is that mining materials and building forts is very loud and can give away your location. In this case, please make sure to stop what you are doing occasionally and listen for incoming enemies in case someone tries to sneak up on you.
Once you are ready to build, it is time for you to launch the mode with the click of the button. From this menu, you are able to cycle through different building pieces, rotate each piece, and use the right joystick to look around and find the right spot to place them. When everything is ready, you can build the structure by pressing R2 on PS4, R on Xbox One, or clicking the left mouse button on PC or Mac.
While in the building mode, you are still able to jump and move around with the regular controls. In addition, you are also able to build any traps you found or hold down the Building Mode button again to edit the structure if you wan to add something like a door. All the things sound like a lot, but with a bit of practice you will be throwing up buildings in no time.
For those who are playing with a mouse and keypad, you are able to speed up the building process even more by using keybind to link certain keys to specific structure types so you do not need to cycle through the options. In order to set it up, you need to open the main menu and click on the menu icon in the top right corner. Then, click on the Settings cog icon and go to the Input tab. From that place, you are able to set up whatever shortcuts you want. As suggested by Metabomb, it is better for you to set walls as Q or E, platforms as F or V, and ramps as F or V, but you should do whatever feels like good for you.