The Render materials window is used to manage render materials. Render materials can be texture files, but RGB colors are also possible.
The Left
column is a list of all created render materials,
sorted alphabetically by name, with the corresponding thumbnail. Above
the 
button, you can add new render materials. And
via 
, the selected entry will be deleted.
As soon as you have clicked on an entry on the left, the ID, Name and Texture license fields are filled in on the right-hand side and the Edit button is active.
Click on to open the dialog box Edit material for 3D preview.
Below this are the settings for Maxwell and a preview image of the material on the project as soon as you have clicked on one.