Lets go over syncing check list.
You have created a resource as yourself, with email that you would like to sync?
You have assigned yourself as a resource to the tasks you would like to be synced?
You have synced your Gantter to your Google calendar by going to File > sync to google task
Wait about 5-10 mins to make sure Google has time to collect the information.
Please Make sure your task in side your Google Calendar is check off.
Then task will appear on the date it will be due.
If you are still not seeing your task in your calendar please let me know.