Gift on order by webkul will enable you to assign free gifts with order, as per the rules defined. To display the gift on frontend, the first step is to select the product you want to add as a gift - by visiting the product section of shopify and choosing the gift on order from app section. You can then create the rules to assign the gifts, set up the minimum order value to become eligible for the free gifts.A pop can be added on the home Page, so the customer is aware about the gifts.