Many first aid posts were located in adapted buildings, such as church halls or schools whose pupils had been evacuated. Others were in hospitals. Unusual locations included the Houses of Parliament and the Dulwich College cricket pavilion.
Some posts were staffed entirely by the British Red Cross and some entirely by St. John Ambulance, while others had a mixed staff that also included probationers and Civil Nursing Reserve nurses. The number of first aiders varied with the size and location of the post.
Each first aid post had three sections: one for receiving and sorting casualties, a second for giving treatment and a third where patients could rest before being sent home or to hospital.
Some posts also had mobile units attached to them, some had gas cleansing stations, many had neither, but the staff felt that every post had its own individual character.
Nurses of the Joint War Organisation would prepare their mobile first aid unit. It could be rushed to the locality of bomb damage to aid the casualties. The unit could also operate from the van or be set up as a small field unit.
The posts were intended to care for the victims of air raids, but blackout accident cases were also treated. First aid posts in air raid shelters and Underground stations often provided basic health care to the people who had to spend many hours under cover.
In all the posts, there were often practice exercises with Civil Defence workers, Home Guard and the police, and training lectures for staff and recruits.