Click Accounts in the Main Menu, then click Add Account at the top right

Fill in the appropriate fields and click Save

Save an excel file of your accounts as a CSV (You can also fill out the Account Template and save as CSV)
Go to the Accounts → Click the down arrow next to Add Account → Import

Choose your file
Optionally manage duplicates, then click Next
Map columns to fields
NOTE: You do NOT have to have fields or columns in the same order or with the same name to import correctly

Click Import, review results, then click Finish