CarDealerPress Plugin Quick Install
Make sure that you have a custom Permalink set in 'Settings' > 'Permalinks'. We usually use /%postname%/.
If inventory doesn't exist on /inventory/ after adding your company ID, go to Settings > Permalinks and save. Then go back to /inventory/.
The CarDealerPress plugin is available from the WordPress admin > Plugins > 'Add New' or you can download and upload it if you prefer.