Status: - MUST be "ON" for Shipping module to appear in your store.
Storefront Icon: - Shipping Icon to be displayed at checkout shipping selection
Auto Select: - You can set to skip shipping selection page if there is only one shipping option. This shipping method will be selected automatically
Accept these payments: - If only specific payment methods are needed for this shipping method, select them here. If nothing selected, all available payment methods will be shown
Sort Order: - Sort Order set's the order in which the Shipping will be displayed amongst others.
After you have made your changes, select the SAVE button.
Note: there are several other methods to allow products with free shipping. You can create Coupon with Free Shipping option and each product have Free Shipping setting. This method works separately from Free Shipping Extension!
Do not confuse with Free Shipping setting on product edit page. "Free Shipping extension" and "Free Shipping per products" are different thing. Say you need to enable free shipping only when Sub-Total amount more than 40 USD - this possible only with "Free Shipping extension"