Zoho Projects allows you to break your existing tasks in sub tasks in order to gain much deeper insights into the progress of a task. Now, simply drag and drop to break tasks in to subtasks or summary tasks based on your project needs.
Import subtasks along with your existing tasks while you import your MS project files into Zoho Projects
This assigns tasks to the selected users and quickly imports all the tasks along with its subtasks from your MPP file into Zoho Projects.
Go to Tasks & Milestones tab
This creates a new subtask for this task. Remember you can add as many subtasks for a task
Few points to remember when you create subtasks in Zoho Projects :
You can view subtasks now as part of your task dependency view. Subtasks gets be displayed if and only if all its parent tasks are displayed.
You can view subtasks as part of your gantt charts. The open / closed subtasks are represented as yellow / brown colors respectively on the gantt chart.
Create a new project template add tasks along with subtasks and save this template for your future projects.
Here's a view of subtasks as part of the project template :