/jp/ - Otaku Culture

help me out with my kanji exams
it's going to be as in picrel, we're given a sentence with two words underlined; one in kanji we have to write in kana and one in kana we have to write in kanji. kana to kanji row is going to be easy problem is the kanji to kana row requires us to write onyomi in katakana et kunyomi in hiragana and I didn't learn any of that
https://www.tofugu.com/japanese/onyomi-kunyomi/#how-can-i-know-the-reading according to tofugu guy
multiple kanji words = usually onyomi
single kanji words = usually kunyomi
words ending with okurigana = usually kunyomi
I was about to go with that but took a look at my kanji class slides and it says
multiple kanji words = usually onyomi+onyomi or kunyomi+kunyomi (no indication regarding it being more often onyomi)
single kanji words = usually kunyomi
words ending with okurigana = usually kunyomi
so which rule do I use for multiple kanji words?