Open Mac Mail and in the top left corner click > Mail > Add Account
On the next screen choose the option > Other Mail Account > and click continue
On the next screen you need to add:
All these details have been sent to you in your email account setup email
On the next screen you will likely see a message that says: "Unable to verify account name or password" This is normal and you just need to add all your details in the relevant boxes
That's it, your email setup is complete, now click "Done"
If you already have other email accounts setup in Mac Mail then you will see your new mailbox located under your inbox folder
Here is a video running through all the above steps