FireCheckout is using default Magento functionality as basic.
After installation If you have some checkout features not working, please, check following:
- Go to
Admin > Stores > Configuration > Swissup Checkout > Firecheckout > General
Enabled > No(please, check if that settings are same at the store level)
- Clear store cache
- Go to frontend, pass to checkout and check if you don’t see that problem at DEFAULT checkout