First off, make sure you're in the workspace that you want to create the list in. You can open the sidebar to check by clicking the top left button, and selecting the workspace from there. Then, tap the Lists icon in the tab bar at the bottom of the screen.
In the "Lists" view, tap the
+ button in the top right to open the New List form. Here, you can name your list and add it to either an existing group or tap the
+ in the Group view to create a new group to add your list to.
Then scroll and select whether you want to share your list with everyone in the workspace or share with specific members. If you want to add "Specific Members", you'll be taken to a list of existing workspace members to choose from. Tap to select and again to deselect. When you're done, click the back arrow to finish creating the list.
You can also add any of your workspace guests to your lists. If you haven't added any workspace guests or want to know more about them, go here.
Once you're finished entering the list details, tap "Save".