After the initial introductory tutorial, you will already own two vehicles; the "Backhoe" and "CT660 Flatbed and Crane". This achievement is really easy to earn.
Press

(Down on the D-pad) to open up your fleet of vehicles currently un-stored. Once this menu pop's up simply press

on either one of the two vehicles. Confirm that you want to store your vehicle with

; this will then be followed with the achievement popping.
An additional note, to retrieve your vehicle you just have to go to "Motor Pool" in the "Company Menu" by pressing

and then select the vehicle with the blue garage symbol, press

and then "Retrieve"
Any improvements, drop a comment and I will do my best to accommodate them. Happy Hunting.