RS-485 Library
Here is a page devoted to the RS-485 BoSL implementation library.
Installation
Extract the src folder from the downloaded .zip file.
Place the src folder in the same folder as your arduino .ino sketch.
Edit RS485args.h (located inside the src folder) to fit setup.
Downloads
Library
Revision 1.0.0 (2020-09-18) : File:BoSL RS485 Bus Library rev 1.0.0.zip