To have the animations played automatically, set the Start "On click" to
"After previous".

To loop the first slide, you can use custom show to achieve this.
First, go to first slide.
Click slide show > slide transition.
Under advance slide, put a checkmark on "automatically after".
Click Slide Show > Set up show.
Put a checkmark on "Loop continuously until esc".
Now, click Slide Show > Custom Show.
Click New.
Add all slides into the custom show except for the 1st slide.
Click ok once you are done.
On the first slide, add an action button that hyperlinks to the custom show.
Put a checkmark on show and return so that it will go back to the first
slide when you press esc key.