If you need to add a transaction manually, there are a couple of ways to do it.
Importing a batch of transactions: you'll want to use our template and import the file.
A single transaction? Then you can add individually.
Go to "Transactions", then choose "Import" on the top left.
Then you'll see the pop up to import a file (with a link to the template).
To add individually, also meaning to type in Puzzle as opposed to importing a file, choose "Add individually". I point this out because you can add more than one transaction that way. It's just that you do it in individual lines as opposed to importing.
Then you'll see the option to enter the information in for the missing transaction.
Be certain to ensure you're posting to the account you mean to! If you can't find the imported transaction, it's usually because you posted to the wrong account.