VICIdial is not designed to be multi-tenant.
However ... this depends on the functionality you intend to expose to the tenants. The Vicidial Group has made a lot of headway on configuring the system for Multi-Tenant and are still focused on completing this task over time, as clients pay, I assume. But while focused on that concept, they may lose track of the fact that there are a lot of circumstances where the present functions already qualify.
So when you say "Multi-Tenant" remember that this is open to subjective interpretation. It's entirely possible that your usage would fit within the present multi-tenancy features (or close enough that some modification would finish it off).
We have also built completely "non-vicidial" interfaces to supplant the Admin features in some environments to allow multi-tenancy. But that was a while ago, before much of the present feature was built. These days, it's more of a "lock out one or two features and build a custom interface for just that portion" and check the next update to see if The Vicidial Group has updated that particular section yet. Or you can just go to The Vicidial Group directly and have them add the piece(s) you are missing by sponsoring those updates at the source.
And as Matt said: Yes, you should be looking at Vicibox.com's iso installer as your starting point. My advice is to have a technician install it in a Virtual server for testing, several times for comfort (with ONE agent it's quite reliable while virtual, just don't go past that). IE: Perfect for development before deployment as well as testing.
After installing with the installer (which has a PDF on the site for installation), switch to The Vicidial Manager's Manual available on EFLO.net (The Vicidial Group's main site). Start at page one and don't skip anything. When you decide you don't need a section and want to skip it, slap yourself, go back and do that section anyway. You'll get a working system that way. If you hit a snag, come back here and look it up or post the manual version, page number, line number, and relevant configuration options plus your problem ... the easier you make it, the more likely it'll be for someone to just answer your question.
Do not attempt to use a mysql cluster. Vicidial requires real-time access to data. However: One mysql server can be used for many Vicidial installations if it has some power. Especially if the Vicidial systems in question are not heavy users. Plus: Vicidial itself can be built as a multi-server system or as several individual servers sharing a DB server (each system having its own DB) or each server standalone with all functions installed.
Happy Hunting.