New babie want to learn about DIY drone

Dear experts,
I had been introduced to this forum for my DIY drone fb group.

Please let me know documents/resources or where to start to learn all this.
I am interested to build my own drone.

I have the DJI Phantom 4 but I would like to build my own one. Could you help me something?

Thanks a lot.

Kind regards

This is the place to start
All the information you need should be there.