Teevity tags
From the dashboard home, go in the the menu to the upper right and select "Preferences":
Teevity tags allows you to filter and split data from your cost bills. If you click on "Show tags available in the billing files", it will suggest you the tags already found tin your previous bills.
Cost partitions
Cost partitions are used to group data precedently splitted into tags.
Retroactive cost compute
To apply your tags and cost partitions setup on your bill history you need to explicitly ask for it.
Warning
This operation might take time (up to a day), and make your billing data unavailable during the operation.