Step 1: add new account
First you are gonna launch Outlook, to add a new account navigate to File > Info > Add Account.
You will get a pop up that asks you to login, instead click the checkbox that says Let me setup my account manually, then click Connect.
Step 2: Advanced setup
Now you wil get a pop up to setup your account manually, you wil be given a bunch of options to choose from, you wil need to choose IMAP.
Next up you wil need to fill in the server and the credentials, then click Ok.
Next up you wil have to specify incoming and outgoing mail servers.
Once you have filled those in you can proceed by clicking Next.
After that your account is ready to use.
In this article we have set up Outlook 2021 for Windows with Plesk.