When you create a package within the Membership settings inside OptimizeMember, you can use these to protect individual pages through the membership settings section where you can set the page level and packages required to access that specific page
For example this page is set to require the "my online course" level and the "package1" package:
To add these package permissions to a user, you would do this when you create your order button or form. The option is provided to add any packages to that user when they complete the purchase of item you are setting up. So you might create a button which gives the user access to level 1 and package1.
You can also manually add packages to a user in the user edit options by adding the packages manually through the custom capabilities field.
Just in case it wasn't explained to you before - with packages you can add multiple packages to a user account so they might have the package1 and package2 on their account. Giving them access to any content that is protected by either of those tags, BUT ONLY if they also have the relevant user level.
So if content is protected with Level 1 and package1, user would need AT LEAST level 1 access or higher, and the package1 tag
Level access works incrementally - so a level 5 user can access content at levels 1-5 but if there is content which is also protected with a package the user would need that package otherwise they wont get access
This is a good way to help separate access to particular content from users with higher level memberships