How do I install Multi-DB using SSH. My database is approx. 100 Gigs and phpmyadmin is useless

My site GTP123.com is a multi-site. I took it offline to prepare and install this plugin – 2 days ago. It is killing me. I must have support very soon please. I have not received the 24/7 support that was talked about. Please help when you can.

Thanks,

Garland