To find games for SRM Online, use the link.
http://shadowcasters.network/srmo/There's a $5 charge to play, mostly to ensure people don't sign up and not show... of you paid, you feel more invested. Obviously, at 20-40 bucks for a 4-5 hour session, they ain't in it for the cash.
Running Missions per the FAQ is legitimate as SSDR says, but unless your an agent, you don't necessarily get access to the CMPs, which are another 8 modules that get released for Agent use.
To sign up as an agent, you need a public place to host open table demos, that means you run Missions on some manner of fair first come first served sign up, at least 6 sessions a year. There are some pretty swag perks of being an Agent...