The feature of AMPSport you will probably use the most is the Coaches' Notes. Here's a video about using the Coaches' Notes.

Step 1. Navigate to the Athlete's Profile Page .

The Coaches' Notes is the third icon (from the left) found below the athlete's profile picture.  

Step 2. Chat about your Athlete.

Only the athlete's other coaches and directors will be able to see what you write here. It should say, in grey, who will be able to see the comment:  

You also have the option to "Email the note to the coaches." You probably won't need this for most entries. This is only intended for notes that are particularly urgent. 

Click and you're finished!