Do you mean using the magnetic reader component of a VCR to sense humidity? So I'm guessing buying one is out? Unfortunately a VCR head won't help you much with this.
Hi pieter, welcome to the forum.
You can start out small first by learning microcontroller basics, since LCDs needs to be driven using programming.
I'd also recommend a cheap capacitive humidity sensor, HCH-1000 (a thread here which has some answers), which needs to be conditioned using cheap electronics. We'll continue from there.