Hello Kot,
setting up environment is really easy
1. start FbEdit
2. select menu [Options]->[Environment]
3. in second box from top (named "Paths:") you can find environment variables which should be set
4. click into "Value" field from line "HELP_PATH" and a explore button will appear (labeled with 3 dots) on right margin of "Value" field
5. click this button and a folder explorer opens
6. navigate to desired folder and close box
7. repeat for FBC_PATH, FBCINC_PATH and FBCLIB_PATH
8. leave environment dialog
On my system result looks like this
https://1drv.ms/i/s!AnXv4gi_KqtPchieHll8AbJ7wqg