We have worked with BinderPOS to make sure our pages work with their standard and premium themes.
In your theme settings, you can toggle on Manage Comics 2, which will add 3 files to your theme, and allow us to write to those files.
In the future when BinderPOS upgrades your theme, you won't lose any changes you've made.
Step 1: Navigate to Online Store, and select Themes
Click Customize
Step 2: Click Theme Settings (bottom left hand corner).
Under "Manage Comics 2 Setup", Click on "Enabled Manage Comics 2"
Step 3: In the Manage Comics app, go to Settings
From Store Settings, set your Theme to BinderPOS (Premium or Standard) Theme
Change the CSS Button selector to .product-addToCart
Click Save.
Manage Comics is now solidly embedded in your BinderPOS theme!