In Finnish, the smaller words get suffixed into the larger one. Take "talo", nominative for "house". In English you say "in (the) house", in Finnish the "-ssa" suffix means the same thing, so you say "talossa". "from (the) house" would be "talosta". There's like over 20 such modifications to the root word, and they compose. "from my house" would be "talostani", where the "-ni" suffix means "my".