Cmd Block (Trigger) TPA

Hi All.
Looking for some guidance.

I want to enable TPA without any plugins. I've seen it done before on a semi vanilla server.

The commands are /trigger teleport set ## and the ## is a Number assigned to players in TAB via scoreboard.

I can not find ANY instruction on how to set this up. Can anyone point me in the right direction or share any knowledge they have on this topic?

Many Thanks,