How can I add taxonomy terms and sub-terms?

1. Go to the Taxonomy Manager in the backend (Menu: "Content" > “Taxonomy Manager”)
2. The displayed categories (e.g. Employment Type) are called vocabularies. Select the vocabulary you want to add terms to.
3. Click Add in the toolbar.
4. Type one term per line. Use one dash for a sub-category, and two dashes for the next level down. If a main term actually starts with a dash, just wrap it in double quotes. 
   Input:

Parent Term
-Child Term 1
-Child Term 2
--Grandchild Term 1
--Grandchild Term 2

Result:

5. Click Add