This project is 2 parts
1) install and configure in plesk round cube mail.
Plenty of guides online. Search google Plesk and Roundcube mail.
2) Task 2 .
My server was migrated recently (plesk 10.4.4 and centos 6.0) and spam assasin was installed via a plesk license. It now blocks mails from Paypal. Amazon, ebay and other important mails.
Even when i have turned off the spam assanian sevice and disabled it in plesk still it doesnt run properly.
So you will need to configure Spam assasin set it to retrain what ever. Find why some mail inst reaching my inbox and configure
DNS zones for DNSBL service and SPF spam protection although this will be only a case of ticking the box and details already filled out.
What i need is a spam and email expert with alot of plesk knowledge.