Tags are labels that are used to identify different attributes for reporting purposes.
To create new tags, go to "Settings" -> "Tags".
Create a tag by going to "New tag type".
Name the tag, assign to an org level, and select the type of tag you would like to have. Tag types are categories i.e Print is a category (tag type) as seen in the image below.
Then click "Save".
This will then create a tag type category, to create a possible value click on "Add a possible value".
Possible values are the values of the tag type's. i.e Print is a tag type, the possible values for this tag could be Newspaper, Mailer, Business card, as seen in the image below.
Click on "Save" and repeat for all the possible values you wish to include for this tag type.
Below is an example of the finished Tag type and the possible values created with the examples used.