You can start to access the content by visiting the Extreme Spec Trials near Detroit.
You also be able to check if you have the new expansion by opening your mobile phone in game and you will be able to see the option "Look For Crew".
If this option is listed in red and is locked it means you do not own the Wild Run. However, if you see the option unlocked this means you own the Wild Run and should be able to enjoy the game play.
After this, you will need to be Level 40 in order to access the Qualifiers and the Summit.