How to Add A Walk
Adding a walk, swim, or chat animation is the easiest change you can make.
Put Mood mixer on the ground, right click it, and choose edit.  Go to the contents tab and drop the walk animation in.
Put Mood Mixer back on, click walk and choose it from the list - it appears in the list automatically!

Did that go by too fast? Dump a walk in and it's ready to use!