My parish's general practice is simply this:
After the period of inquiry, when a formal decision is made, then the inquirer is made a catechumen by an initiatory rite.
After this, the catechumen is expect to attend as many services as reasonably possible for one year. This whole year allows the catechumen to experience the full cycle of seasons. It's also usually enough time to weed out any overly zealous anxiousness or for those with a mere curiosity to lose steam, but more than that, it calms your nerves a bit and gets you into the rhythm of things.
I know that a year is excessive in many circle these days, and receptions are more likely to happen in 3-6 months in a lot of churches, but in the ancient church the catechumenate lasted for three years, and after the liturgy of the catechumens (the first half of the liturgy), then catechumens were expected to leave and wait out in the narthex and listen to the prayers. They weren't even allowed to be around the Eucharist, let alone those who had not been initiated!
No set rules on classes or anything. Just come to what you can, when you can.
All of this will be different in your specific parish, so just go straight to a local priest and ask him.
This has been my experience as well in my OCA parish. I'm actually in the middle of the process right now. I will remember you in my prayers tonight.