How to link multiple Doctypes

Hi am new to frappe.

Am trying to achieve following requirement.

I have to create a Contract with Multiple Projects DocType, and each Project will have Multiple Locations DocTypes, and each Location will multiple small Areas DocTypes.

so this scenario is based on one to many relation.

For this i have created 4 normal DocTypes and 3 supporting child Doctype with Table and Link fields.

Now when i make entry for the data, i can able to enter all information for each DocTypes.

Now my problem is when a user click on any contract in Contract List, He can able to see the contract detail and all projects list in table that are related to that contract.
I want to know how i can link the project from list to all location of that project and each location to area list.

Because when i click on project it showing the following edit form, i just want to go to list of locations of that project.

Try Table MultiSelect or child table to achieve this

Yes, am using child tables. But my problem is i want to achieve like

From Contract List, if user clicks on any contract it should go it’s contract detail with project List (this working) → from contract Detail page if user clicks on any Project item from list it should go to it’s Project detail page with Location List →
from Project detail page if user clicks on any Location Item it should go to it’s Location detail with Area List