The app is built around container profiles you create for all the fuel containers (tins, jerry cans etc) you use regularly. Simply press the plus button in the top right of the main screen to create and configure a new container.
Choose “Random Mix” for a one off batch of premix two stroke, select your Fuel:Oil ratio and how much fuel you would like to mix and the app will tell you exactly how much oil to add.
The apple watch doesn’t have a lot of processing power or very fast connections, especially the version 3 or earlier. So it takes a little while for it to process the iCloud sync information. Please be patient, it should only take 10-20 seconds.