I want to learn grails and i want to use IntelliJ IDEA and my professor said that I could connect grails to IntelliJ IDEA but i dont know how. Can you please help me with
There are a couple of good pages that can help you:
http://www.grails.org/IDEA+Integration
http://www.jetbrains.com/idea/features/groovy_grails.html
You can create your Grails project using Grails console and then import it into IntelliJ or you can create it directly in IntelliJ, I think it is a matter of preference since both ways work just fine.