A lot of theatrical stage lighting design is based on and has evolved from Stanley MxCandless book A Method Of Lighting The Stage https://archive.org/details/methodoflighting00mcca
This lighting design method provides Visibility, Selective Focus, Modelling and Mood.
If you look at Choosing Lighting Positions in Lighting The Amateur Stage by Francis Reid https://www.theatrecrafts.com/archive/documents/lighting_the_amateur_stage_1.pdf you will see that lighting straight on from the front restricts your lighting design.
This booklet and the second volume https://www.theatrecrafts.com/archive/documents/lighting_the_amateur_stage_2.pdf provide an excellent summary of stage lighting for amateur theatres and schools.
Theatre 476: Stage Lighting
This is Professor Paul Collins website at Central Michigan University http://thtr382.weebly.com/
There are a lot of photos and videos in each section to help explain and visualise each section.
Elements of Light
Functions Of Stage Lighting
Dimming & Control
Lighting Design Process and Paperwork
Research & Inspiration
Systems and Specials
The Light Plot
Page Updated 15 February 2022