If you are already having in YMM standard version in your site, no need to do again admin setting for this module, you can keep using existing attributes, attribute set and cms page.
Step 1: Rename or delete Ymm folder and Kamtech_Ymm.xml file in the following respective path from the server app/code/local/Kamtech/Ymm and app/etc/modules/ Kamtech_Ymm.xml. Refer the below screen shot.
Step 2: After Renaming or deleting the above mentioned file and folder, please clear cache of the site.
Step 3: Take Ymm and Kamtech_Ymm.xml from the received upgrade package, then place that file and folder in the following respective path in your server app/code/local/Kamtech/Ymm and app/etc/modules/ Kamtech_Ymm.xml
Step 4: Clear cache of the site.
While upgrading from Standard to Professional version a Master table will be created in the database of site. The master table name is year_make_model_master
Only 1000 ymm records will be populated into the master table while upgrading this module. For remaining records, Please import via YMM_Data_Importer module (You can find a package for it from the received package)
For YMM_Data_Importer, Please refer the below link for installation steps and how to use this module. http://mage-extensions-themes.com/wiki/ymm-data-importer/
For any questions or issues, please contact technical support team via http://mage-extensions-themes.com/support/