Combining multiple projects' to-do list into one master to-do?
 

I am trying to organize my projects and what needs to be done for each
project. Is there a way to 1 of the following:
1. create a master to-do list and then have each individual task to be
added to the proper project?
OR
2. (which i have now) individual projects have a to-do list and want to
combine them into one master list.

thank you.