Good first aid can be the difference between life and death for an animal in distress!
The main aims are to preserve life, prevent deterioration and promote recovery. The important thing to remember is that you don't necessarily need to be a direct part of the whole process!
Good first aid also involves knowing when something is too much for you! First aid could look like putting an animal in a cardboard box with a cosy towel and transporting them to your nearest veterinary practice. In doing this you are:
Preserving life: By containing the animal and taking it out of danger.
Preventing deterioration: By removing potential negative factors like poor weather or predators.
Promoting recovery: By taking them somewhere that can provide appropriate care.