Adding several different accounts at the same bank is easy - when you get taken to your bank you'll be presented with all the accounts that your bank has enabled for Open Banking, and you can select all the ones you want to share with Armalytix:
If you already connected the bank to Armalytix and didn't connect all the accounts, you'll need to disconnect the bank and reconnect it.
To disconnect, hit the šļø icon next to the bank:
Then you'll be able to reconnect the bank and select all the accounts you need.