When you select the Accounts command, the Accounts dialog screen will be displayed. To add an account, you will need to enter both an account name and number. If you enter a name or number and the other changes by itself, then that name and number are already in use. If this happens, select another name and number.
Currently, income account numbers are in the 400s and expense account numbers are in the 500s. Use another system if you find it convenient.
After selecting a unique combination of name and number, click on the Add Account button. The new account will be added to the Accounts worksheet.