Please visit Templates to get to know how templates work first. The only way to edit a team page is by customising the custom-team.hbs file itself. Don't worry, it's basically copy-paste work with some text changes. Below is a snippet of the code you'll need to make sense of things.

<h2>Server lead <span class="teamCounter">4</span></h2>
<div class="team">
    {{> team-member name="Chersus" rank="Server Administrator" img="<https://cravatar.eu/avatar/Chersus>"}}
</div>

The basic structure of a teams section is as follows:

• h2 title + span with count
• div team wrapper
  • team-member components requires: name, rank optional: img

Currently, the teamCounter doesn't update dynamically, therefor you'll have to do some counting yourself and update the number. I'll set up a new example so you start to get the idea.

<h2>Server lead <span class="teamCounter">2</span></h2>
<div class="team">
   {{> team-member name="Chersus" rank="Server Administrator" img="<https://cravatar.eu/avatar/Chersus>"}}
   {{> team-member name="Random" rank="Server Owner"}}
</div>

<h2>Server moderator <span class="teamCounter">1</span></h2>
<div class="team">
   {{> team-member name="AnotherRandom" rank="Server Moderator" img="<https://cravatar.eu/avatar/AnotherRandom>"}}
</div>

If you're using the theme for MineCraft, consider heading over to cravatar.eu or mc-heads.net to create a link to the skin head.