No signal on hdmi

Guys hope you can help. I’m an ultra novice and bought a PicAde to build with my lad. We have built it and downloaded software etc. the only issue is that we can’t seem to get the hdmi signal to register and work? Any help gratefully received

Try putting hdmi_force_hotplug=1 in your confix.txt file. I do believe that will force it to use HDMI.