If you encounter a missing Ticket Types and Discount Codes menu items in Tickera menu and Settings area is missing Payment Gateways tab and overall offers different set of options than you used to find there, that means that you have installed and activated Bridge for WooCommerce add-on. When installed and activated, this add-on changes the way Tickera is used. For example, ticket types are created as WooCommerce products and complete "selling part" relies on WooCommerce defeating the purpose of Tickera's payment gateways. Therefore Ticket Types menu item and Payment Gateways in Tickera becomes obsolete and is removed as soon as this add-on is activated. Same goes for the Discount Codes; as WooCommerce is taking care of the checkout, its Coupons are then used. More about setting up and using coupons in WooCommerce can be found in their documentation page here.