Build an Online Store - Variants

I make custom shirts out of my home. I would like to open a Shopify store and sell these custom shirts online, but I need a way for the customers to pick a fabric pattern, location where they want it placed on the shirt and to see these changes visually so they can play with different looks before committing and progressing through checkout. I currently have the Shopify store (not launched) and theme. I am within the 30-day trial period for Bold Apps Product Builder, which I have been adding variants to (shirt color, sizes, etc.) but have no clue how to visually see changes in real-time. Example of what I have in mind: [login to view URL]