"It is bright in our school."
Translation:W naszej szkole jest jasno.
"Thanks to declensions, word order doesn't matter in Polish" is the worst advice I've ever heard when I started to learn Polish. Thankfully, you realize it's ❤❤❤❤❤❤❤❤ pretty quickly, like... just after one told you that so you try changing word order of a sentence in different ways and everything is wrong.
English is strange language that makes you use subjects when they are not only unnecessary- but nonexistent what is exactly that "it" that is bright, or rains? (Polish girl who learns English POV)
Simply use "to" only when you can replace it with "this" and on/ona/ono when you know (or in context of translation can imagine) what the subject is and which gender to apply.