I made two subfolders: Task and Project in my workspace.
I saw in the Project Planning template, there is a possibility for me to assign tasks to a particular project.
But seems I cannot find how to assign tasks to a particular project item.
Please help how to do this?
Hi there @putomo 
What you see in our Project Planning template is links between two items (projects and tasks), they are made through our attribute called reference.
Reference attribute allows you to link items from one folder with items in another folder and in that sense create relational databases.
Feel free to click here in order to learn more about references and how you can potentially use them.
Here’s also a short video showing you how that can be done.
Hope that helps 
Cheers 