UE4 usually detects if a new module is built and does an automatic hot reload.
If that doesnt happen by default try using the manual hot reload (Compile button at the top of the editor) instead of building in visual studio
If for some reason hot reload doesnt work at all you will need to restart the editor in order for the changes in code to be applied.
Also for variables and functions (UPEOPERTY / UFUNCTION) to show up in the visual/blueprint editor it needs to be restarted (doen’t matter you used hot reload or not).