A Variant ID is another way for a Shopify store to keep track on inventory, and more specifically sizes for products.
In the example below, you can see that the first ID code (928289226799) is for the general product. Whilst the IDs below under "variants": are the ones you need to be able to use a variant inside Cyber.
EG 9006675787823 would be a US 8 variant ID for this specific product on Blends US.
To use a Variant ID inside Cyber, simply open the bot, go to create task, select the appropriate store (In this example we're using Blends US) and enter the variant ID as the keyword.
You can input any size, as the bot will ignore this completely since the variant ID is specific to a size anyway.
Then you'd simply start your task as normal!
Variant IDs are not always available before a release so they're more often than usual used just for running for restocks as they can be a tiny bit faster than using keywords/links.