A variation in Square is a type of item - it allows you to apply different pricing levels to an item. As such, these are synced to your Doshii menu as items - if you have three variations, eg small, medium and large, there will be three items in your Doshii menu for these.
If you want to use these variations as variants in your App menu, you will need to create an Option set in your Square POS, which will sync to Doshii as variants.
What can you do?
Create Options Sets in your Square POS. These will flow through to the Doshii menu as options and variants that can easily be linked to menu items in your App menu. Please read this Square article for more information on how to do this.
You cannot create POS items and options in Doshii; they must be created in your Square POS. Any changes you make to your menu in your Square POS will automatically sync to Doshii.