For this example, we will take a look at the "Downloaders" group

When reviewing permissions you can click the "?" icon to explain the site interaction that each permission will allow this group 

Let's say we want to give members of the 'Downloaders' group permission to "Create collections"
To do this we tick the box next to the permissions and click "Save"

Let's say we want members of the 'Downloaders' group to have permissions to "Create collections"

The 'Downloaders' group will now be able to create collections

Grant permissions to a group of users