Dear Antonio Lopez,
For Hide buttons ("Add Vehicle" and "Search Vehicles'
you need go to VehicleManager : Settings - Frontend Settings -Buttons Settings
Show button Add Vehicle - put No.
If you want that managers can add inventory (Vehicles) , as I understand you need for same button Show button Add Vehicle choose Yes and with Allow button select group, which will be able add new item.
Search Vehicles button can be hide only via code, give us link where you want hide it, and we will explain how you can do that.
Thanks,
Taras
OrdaSoft team.