How to set up data security policy

Summary:

How to create "Condition" for a Data Security Policy

Content (please ensure you mask any confidential information):

I'm attempting to associate a custom role with a data security policy. There are several that a contractor configured for us, which restrict the access of attachments on an item to users in a role via the attachment "Category".

The role looks like this:

Based on other articles in CCC, it looks like I need to set up that security policy here, but it requires a "Condition". Clicking on Condition shows a list of pre-defined conditions in a list called "Pick a Database row". How are these Conditions created?