To select Related Products, Follow the below steps.
Step: 1 => Open the ShagunBox app and choose the Related Product app from the side menu.
Step: 2 => Scroll down, Here you can see a list of all products, In this list, you have to choose one product (See screenshot below).
Step: 3 => Now click on the Select Products Button (See screenshot below).
Step: 4 => You can see a list of products that can be used as Related Product, Now in front of the product click on the checkbox, to add that product to the related products list (See screenshot below).
Step: 5 => Now click on the Save button.