There are three Set Input Mode nodes that are used to define whether the priority in handling user input Events is with the UI or with the player input. These are the nodes:

• Set Input Mode Game Only: Only Player Controller receives input Events.
• Set Input Mode UI Only: Only the UI receives input Events.
• Set Input Mode Game and UI: The UI has priority in handling an input Event, but if the UI does not handle it, then Player Controller receives the input Event. For example, when the player overlaps a Blueprint representing a shop, a UI is displayed with options for the player to choose to use the mouse, but the player can still use the arrow keys to move away from the shop:

I recommend you get used to these miscellaneous Blueprint nodes. When working on a project, you will have to deal with some problems that can be easily solved with some specific Blueprint nodes.