To create a new material from an image follow the Add a Materialpage and select the From PBR Files option.
The click on Create.
This will open a new material dialog, where the texture set, with the placeholder maps are already created, where you will be able to drag and drop your maps:
Drag and drop your maps to the slots that best describe the map you are trying to upload and then also enter the physical size of the maps, like so:
then click on Save. After these steps now there is only one step left to do, which is to click on New material: