how to sync todolist with my google calendar？
Head to Todoist.com, top right corner, gear icon, Settings. From that new pop-up there is an iCal feed URL listed, this is what you need to copy and paste into GCal. As a new subscription.
Can I see my google calendar items inside my todo list will they sync that way?
At this time no they will not. It is only one way sync. If you want to check out Sunrise Calendar it does sync both ways.