General question about troubleshooting PCB parts

Hello,

I am troubleshooting blown backlight on this tab and am kinda new to PCB. Before ordering complete new display unit wanted to check the logic board to see if everything is ok.i found a scheme on the internet, see below.Could you please spare some general recommendations how to do it?

Currently using kinda cheap multimeter where i taped clothing pins to the wires so that i can read even small connections.

Thanks