How can I get all my transactions from my bank account to link to quickbooks, as some from when I first opened the bank account aren't showing?
Welcome to the Community,
So if you have missing transactions in the banking section, you can manually csv import them in so that they then show up for you. If you have a look at this link it will show you the format on what the csv needs to look like in order for it to upload correctly into your Quickbooks account. Also if you have a look at this link it will show and tell you how to upload the transactions from the bank and into Quickbooks here.