Best way to start?

[jch]

hmmmm... I can't find that I sent a high school transcript to TESU as proof. Did others have to send a transcript of high school graduation to TESU? If it matters on that, I'm US citizen in the US.

Same here, I never had to send TESU any actual evidence of high school graduation. While I think I had to fill a section on the application attesting that I had completed high school, there was no further verification. To my knowledge, my old high school does not participate in any clearinghouse or electronic verification system either.
I'm also a US Citizen in the US.