Recommended publications for study (free download)
[1] Donald L. Stoner (W6TNS)”:The Ham Radio Handbook – https://archive.org/details/TheHamRadioHandbook_201904
[2]A. Frederick Collins: The Radio Amateur’s Hand Book – https://www.gutenberg.org/ebooks/6934
[3] Petr Ondracek: Fundamentals of Radio Spectrum Management – https://www.vovcr.cz/portal/topic/504?displayType=blocks