You can add keywords manually, get keyword suggestions and even import keywords from a CSV file. Here is how to do the import.
Go to the Keywords section.
Choose an Excel file to import.
Click Choose File.
Import limits vary depending on your subscription. Contact your sales rep for more information.
You should see your new keywords displayed on your keyword list in alphabetical order.
It may take a few minutes to load all the data associated with each keyword. Meditate on the meaning of life.