You will not see any help messages or advise like "Not rod equipped, no hook, no bait" if you play in realistic mode.

You need the Unity Mod Manager from here:
https://www.nexusmods.com/site/mods/21

Then install my mod from here:
https://www.nexusmods.com/ultimatefishingsimulator/mods/5

Start the game and make sure the mod is "green" (enabled).

p.s. Not sure, but I guess it is best to have the game installed into: C:\GOG Games\

pps. before you update the game, open Unity Mod Manager and uninstall -> update the game -> install