At the beginning let's explain why do you need the Bridge for WooCommerce plugin.
Essentially, as the name suggests it is a "bridge" between Tickera and WooCommerce. With this plugin installed, you will be able to create Tickera's ticket types as WooCommerce products (which is thoroughly explained here). Also, Bridge for WooCommerce will make it possible for Tickera to "communicate" with WooCommerce and vice versa. So, for example, if a customer purchases a WooCommerce product that has been declared as a ticket, a ticket instance will be generated in Tickera and the ticket download link will be sent to the customer.
Installing Bridge for WooCommerce is fairly simple and is described in our documentation page here.
If you have already used Tickera as a standalone (without Bridge for WooCommerce) and decide to switch to the "bridge mode", all of the tickets sold while in standalone will become inaccessible! Therefore, we strongly advise you to start using Tickera in "bridge mode" at the beginning of the ticket sales for your event or if you have ongoing ticket sales in standalone mode, finish it that way and then switch to the "bridge mode" for the next event.