How to manage accounts
Although there's plenty of variation that you can apply here, this is how I recommend you manage accounts.
See also:
Asset accounts
Create one asset account for each bank account you have. Also create asset accounts for your savings accounts and credit cards.
Other financial apps advise you to save your credit card as a liability, but in Firefly III I recommend you create it as an asset account.
Liabilities
Create a liability for each outstanding or incoming loan. For example, your mortgage or student debt. Set the amount as a positive number.
Other account types
You don't need to create expense accounts and revenue accounts, they are automatically created when you create a transaction.
IBANs and account numbers
If you can, add IBANs and account numbers to the accounts when you know them. This will help you when importing data.
Deleting accounts
If you delete an account, any associated transactions will be removed as well. If you're deleting an asset account, and you've transferred money between the current asset account and other asset accounts, you might see changed balances all around. Remember to correct this, if necessary. You can move the transactions to a new account if you wish to preserve them.