Meetup Group URL: You need a meetup group URL. So you have to go meetup.com and copy your group name from the URL. Example:
http://www.meetup.com/your-group/

Import type: If you choose one-time-Import it will import only one time. If you choose scheduled import it will give you the option by once Daily, Once Hourly, Once Weekly.

Import into: If you choose WP Event Aggregator your event import into WP events.

You can see events on WP events .so this way you import your Meetup event using  Meetup Group URL.