How do I create a product that has variants?

First, create a new product which will serve as the master product. The master product is never sold. It is just the template that the variants are based on.

Log in to the Onsight web console at https://sales.onsightapp.com/.
Click on ‘Manage your data’ from the left-hand side menu.
Click on the ‘Master products’ menu item.
You will see a list of all of your existing master products.
To add a new master product, click on ‘Add Master Product’.
Fill in a name and a description for the product.
Choose a category for the product.
Optionally, you can also specify a price and upload an image.
Click the ‘Save’ button.

Now, we can create the various variants:

Click on ‘Manage your data’ from the left-hand side menu.
Click on the ‘Products’ menu item.
You will see a list of all of your existing products.
To add a new variant, click on ‘Add Product’.
Fill in a name for the variant.
Choose a category for the variant. It must be the same category as the master product.
The ‘Master Product’ field will appear. Select the master product that you created in the previous step.
Optionally, you can also specify a different price and upload a different image.
Click the ‘Save’ button.
Repeat this for each variant.

After you have done this manually for one product, you can use the bulk import tool to upload all your masters and variants using an Excel file. See: How do I bulk upload my product catalogue.