How tough to get started?

[Jack]

Yes, Mike, a turkey choke is a tighter constriction than your full choke tube. Usually a turkey choke is longer, too, and may have some holes, etc to help the wad separate from the shot charge.
Check your state regulations for what shot sizes you can use. Turkey loads tend to be heavy payload, high velocity loads with shot sizes between #2 and #8. The idea is that you want to put a dense pattern of shot on a turkey's head/neck area. Turkey feathers are big, and can stop a lot of shot- enough so that a body shot is ill advised.
As far as calling videos, remember that the guys making those videos are selling videos and calls- they make it sound like you have to be a world champion, and use only their magical call. All of which is crap. Learn to yelp and cluck on your box call, and go hunting. And remember this: not all people sound exactly alike- and neither do turkeys. If you don't sound quite like Joe World Champion, don't worry about it.