Version 4.8.6 and Older:
The Documentation for aCar can be found within the app. While on the App Homescreen, click on 'FAQ'
Version 5.0 and Newer:
Visit our Documentation Site for aCar 5.0+ here
You can also find in-app documentation by heading to 'More Options...' then 'FAQ'
If you're unable to find your answer in the FAQ, try the Forum.