In Fortnite: Battle Royale, you have a default Inventory, which you can use in any way you want. In the inventory, there are five slots for weapons, gear, Meds and grenades, plus a separate slot for ammo and building materials. At any time, you can have 999 ammo of a given king on you (you are not going to need more, anyways) and just as many materials. The pickaxe assigned to quick selection #1 stays there and it is the main tool for obtaining building materials. Also, you can eliminate an opponent using this tool, but it is pretty ineffective for combat, so its only default function is destroying objects on the map.
After you have accessed inventory (default key and for PC) you will be able to modify your gear. Here, you can place items in quick access slots (in any way you wish, including the pickaxe). In duo, or team game modes, you can use this window also to drop items and share it with a teammate. The same goes for ammo and building materials. Do that to share items with other players that lack them in their inventory.
Swapping owned weapons is especially useful when you learn hotkeys by heart. In this case, it goes without saying that the first weapon is assault rifle and the second is sniper rifle.
In the game, there is an item class system, present also in such games as Borderlands or Destiny. Item’s performance depends on its rarity – the rarer, the more effective. However, these are not glaring differences, but ones of several percent. However, if you want to have the upper hand over your opponents, you can try to collect the best weaponry. Usually, such items appear in the number of several units all around the map, and you have the greatest chances of finding those in supply drops and on corpses of killed opponents.
Note! The most important issue, when it comes to class system, concerns assault rifles. White, green and blue are for M16, whereas purple and orange are for SCAR. The latter, in spite of the lack of any description, is much more accurate than M16. Take advantage of that while fighting over long distance. To learn more, see the chapter entitled « Firing System ».