How to add assets to library

Here's a step-by-step process to add material to library 

Step 1 : Extract the downloaded zip to a location where you want the library

(*Note : you can use the blend file but the zip file contain custom thumbnail images and catalog file)  

Step 2 : In the main menu at the top of the Blender window, click on "Edit."

Step 2 : From the drop-down menu, select "Preference" 

Step 3 : Blender Preference window will appear. in that window select 'File Path'

Step 4 : Scroll down to Asset libraries tab and click on the '+' button

Step 5 : A file browser window will appear, Navigate into the extracted folder

Double click to open the folder

Step 6 : Now click 'Add Asset Library" button 

Now the assets will added the asset Library

Step 6 : In asset browser , click the asset list menu and select Clock or All

Now you can drag and drop the clocks and customize the material in node editor or Material property tab