To open the doors, click on them on the car and the doors will open. click on the door again to enter. To close the doors, press the door WHILE moving/crouching.
DISCLAIMER
This Cars Mods is an unofficial application for minecraft pocket edition. This application is not affiliated with Mojang AB, the Minecraft name, the MCPE brand, and all Minecraft property is the property of Mojang AB or a respected owner. According to http://account.mojang.com/documents/brand_guidelines