Hello A. Astinbo,
If you don't have a to-do list tab for your outline file, you'll have to create one. Here's some guidance for doing this in the PC desktop version of MLO:
The tabs bar is just under the menu in MLO. At the right-hand end is a "+" button, which you can use to create new Workspace tabs. The first thing you can do is to rename your new Workspace. For your main to-do list view, it's a good idea to tick the checkbox for syncing selection with the first tab - That way, you can double-click on an item to jump between viewing it in the outline view and the to-do list view.
In your new Workspace tab, you need to choose which "View" you want to see. If you can't see the Filters and Views pane on the left, you'll have to press Alt-F1 to make it visible. In this pane, you can either select your list of Views, or you can bring up the Filter criteria, to make your own View up. (If what you're seeing is headed "Filter", click on that heading to close down the Filter criteria list and show the list of pre-configured Views.)
The group of To-Do list view is a set of the predefined views you can select for your Workspace, although you can also create your own, custom Views.
I hope I'm not confusing a new user with the distinction between Tabs, Workspaces, Views and Filters in MLO. A Tab contains a Workspace which shows a View, set up with Filter criteria. You have complete control over how you set all of these up, although the learning curve, especially with the language for Advanced Filters, can be a bit steep at first. However, once you have an outline View in one Workspace and a synch'd ToDo View in another, you can take your time to learn the rest and customise MLO to work exactly how you want it.
I hope that helps,
Stéphane