Learn Finnish: Me laulamme saunassa.

The dictionary form is laulaa (to sing). It ends in two vowels, making it a Type 1 verb. To make the "we" form, you drop the final -a to get the stem laula-, and then add the "we" ending -mme.

Can I drop the word me and just say laulamme saunassa?

Yes, you can! Because the verb ending -mme already means "we", the pronoun me is optional. Finns often leave it out unless they want to emphasize exactly who is doing the action.

How does the word sauna become "in the sauna"?

By adding the ending -ssa directly to the end of the word. In Finnish, there are no separate little preposition words for "in" or "on". Instead, you add endings to the nouns. So sauna becomes saunassa.

Will the ending for "in" always be -ssa?

Not always. Because of Finnish vowel harmony, words that have front vowels (ä, ö, y) take the ending -ssä instead. Since sauna has back vowels (a, u), it takes the back vowel ending -ssa.