Jira sync can only be down with sync to Jira processed projects. You are given one to start with and have the option to create more. These projects are shown on the app as having a blue sync with Jira title and on the PC as having a sync icon next to the Project title. You can sync with JIRA by pressing the sync icon.
You will then be redirected to a sync screen where you will be asked to enter in your JIRA information. From there choose your desired settings and click sync. Your Effi reports will then appear in Jira.