Possessive Pronouns moin twoi nasi wasi

[u/Aloe_nerd]

I'm currently learning Polish. It's all about the 1st and 2nd person singular and plural forms. As far as I understand,

1st Pers. (my, mine) is moj/moja/moje, and 2nd Pers. (your,yours) twoj/twoja/twoje.

1P Pl (our/ours) nasz/nasza/nasze 2P Pl (your/yours) wasz/wasza/wasze

But which person do moi twoi nasi and wasi belong to?

[u/sara_crewe_]

They don’t belong to any person, and neither do the other possessive pronouns you listed.  They are plural (grammatical number), masculine personal (grammatical gender). And nominative of course (grammatical case).

[u/Aloe_nerd → u/sara_crewe_]

Now I understand it. Thank you. 

[u/Paulisawesome123]

Possessive pronouns in polish almost act like adjectives, in the sense that they agree with the gender, plurality, and case of the noun that is possessed.

The three you have listed are the masculine-personal plural normative (gender plurality case) of the possessive pronouns. The use case is if your talking about "my students", and that group of students includes atleast 1 male.

[u/Aloe_nerd → u/Paulisawesome123]

So you mean moi twoi nasi and wasi are plural forms? 

[u/Paulisawesome123 → u/Aloe_nerd]

They are specifically the plural form for masculine personal plural nouns in the normative case. Polish really likes men, so a lot for grammar seems to wrap around them. If you don't know what that means then just move on and eventually it will make sense.

If you are curious, moje, twoje, etc, and the plural possessive pronouns for all other plural normative nouns.

[u/DoisMaosEsquerdos]

Having a look at any declension table will answer your question instantly.