To add name plate to other actors you can follow the video below. There is also more infomation about the component below.
Name plates can be added to any actor not just players, you can take a look at the example cube blueprints. When you have a name plate component added to a blueprint you can select it to change the look of the name plate.
Here you can set some of the setting for how the name plate will look like font size, bold text and color, just make sure you tick on Use Component Text Settings if its unticked the settings in the widget blueprint will be used instead. If you want to make more changes to the name plate you can do this in the widget editor of the widget you are using. The default name plates are the BP_BP_FloatingNamePlate_01 and BP_FloatingNamePlate_02.
You can also set if the name plate should hide when out of line of sight and if they should hide at a distance.
The name and guild text is set using the interface events in the blueprint you added the name component to.
The output string of these function control what the name plate displays, make sure the Boolean out of the Show Name Plate is ticked on if you want the name plate to show.