Once you have created and populated your List you can add it to options shown at the top of the screen. Click on the List name to open it. At the top right of the screen is an option to Pin it. This will add that list to the feed options on the right of the screen. It can then be moved up or down.

To populate the list you go to a person's profile. Click on the three dots just to the right of the word following. The select the add to list option. That individual can then be added to any of the personal Lists you have created.

Those are my custom Lists that I have created. You click on the word List above your Profile on the left side of the screen. Then you can create any custom list you want.

Here is a screen shot of mine. It is a combination of Feeds and Lists.