blind person built PI with 7" display but it never worked

[4PLUS]

I qm here looking for solutions to help my student. Student is taking a college class and building a Pi is for a grade. Student is blind. It appears the student followed all instructions for assembly. There is a red light, but the 7" display shows nothing. Help me support the student's independence. What has gone wrong?

[aBUGSworstnightmare]

Re-check all connections (5V power supply and DSI interface cable) and post some pictures how it's assembled

[B.Goode]

Help me support the student's independence. What has gone wrong?

Maybe query whether an appropriate Operating System has been installed onto a microSD card and inserted into the Raspberry Pi before powering on?