Group riding
Riding in a group is a skill that comes from practice. It's normal for the first few group rides to be daunting. Familiarising yourself with the video below will help a lot, as will letting the ride leader know that you're new to group riding.
More ride guidance to go here...
Accidents
Accident guidance to go here...
Concussion
A fall on a bike can often involve a blow to the head. You may feel fine but keep an eye out for the symptoms of concussion. British Cycling have produced a helpful guide on this: