In order to create a variable product in ERPAG, first you need to create the wanted variations by going to:
Inventory > Product properties > Add new
Once you've donr that, you need to assign the created properties to the wanted products in your inventory. Go to:
Inventory > Product and services
Choose the wanted product from the list and open them. Click on 'edit' to enable changing. Scroll down to the 'product properties' section, expand it and choose the variations from the drop down menu.
Once you are done creating the variations, you can move forward and create the variable product.
Inventory > Products and services > Add new > Variable products
This will open a window where you will enter the necessary information for the master product and in the 'product variations' section, you will add the variations for this product, by choosing the from the drop-down menu.
Once you save the changes, the variable product will be added to your inventory.