Go to Settings > Store Info
Look for the setting 'Manage Inventory' and enable
Adding a New Product
Go to Products > Add Product, advanced options
Determine if you will be entering in a website or POS product - you can manage inventory for both. When you are finished filling in the products basic info, scroll down to Advanced Options. Choose 'Yes' for Manage Inventory setting. You will be able to enter units here as well.
Editing an Existing Product
Go to Products > Product Catalog
Select from the drop down to see either your existing POS or website items.
Once you select the type of products you'd like to see, you can view your items and edit them as needed.
Go to Products > Inventory
This is the screen that will show you all of your products that you have enabled tracking for and their units. When a unit a product gets sold, then the unit will be automatically subtracted from this list.
Print Report - Will allow you to print an inventory report with product ID, name, unit price, and units available
Export Report - Will download a .csv/excel spreadsheet to your computer. Provides product ID, name, unit price, and units available.