On this page, you can read what the Armory and Stash are for in Diablo Immortal and how to use them. You will learn how to create gear and skill sets.
The heroes have access to the Stash in each settlement, and their content is shared by all of them. It is a good idea to store items in them that you may need later. An important piece of information is that the Armory is connected to the Stashes.
In Armory, you can create a Loadout. This allows you to prepare your hero for various activities and matches - create a build for bosses, effective exploration and fighting numerous opponents, or fights against other players.
To save a build in the Armory, equip the hero with the items you want to use and create a skill set. Then open the Armory and save the current build. Items you put in your Stash will be automatically assigned to the hero when you switch the current build. However, you cannot load a build when you are outside of the Armory.