You start of by visiting the ticket details page and pressing on the Lexzur Connector add-on icon. That will open up the add-on's section and in it you will see a Connect to Lexzur Contra. As shown in the screenshot below.
After that you will be promote to login via your email into your Lexzur account. As shown in the screenshot below.
Once login is successful you are good to go. The next step would be linking your contracts. (here)