Pick a size, pick a colour, then open a style to copy its code. Every badge updates itself with the live player count.
GameTracker's default banner size, so it drops straight into an existing slot.
<a href="https://mantascope.com/fivem/server/dying-light-rp-1289914"><img src="https://mantascope.com/server-img?id=1289914&size=banner&style=poster&color=auto" width="560" height="95" alt="[Qbox Project] Dying Light RP" /></a>