If you are using Salesforce Classic please refer to the article Adding Yoxel tabs.
Otherwise click the App Launcher icon and start typing 'Yoxel'. The 'Yoxel Sync' item should be found under Items. If Yoxel Sync is not found please ask your admin to check the Yoxel Sync package permissions: Enabling users to access Yoxel
Click the Yoxel Sync item and a new tab will be added to your menu. Drag it to the left to place it where you want on your menu: