I can explain to you about plesk and their functionality, then guide you one by one for ex: how to create account, reseller, plans, subscribe, resources, tools, components installations, manage services through plesk, make dns, make share IP and host multiple domains on same IP, backup schedule, restoration, migration accounts from one plesk server to another, database, backup database, restore database, use webmail, change webmail from horde to rouncecube, multiple php version, which qmail to postfix. check mail queue. use internal firewall etc.
Please PM with me for more details and start it.