Here you can find some main topics on Finnish grammar.
Introduction into Finnish
What kind of language Finnish is, how Finnish is different from other languages.
Phonetics deal with sounds. This gives an introduction to Finnish vowels and consontants, and explains how to pronounce Finnish.
Verb is the "head" of a sentence, here you'll find how to use verbs in Finnish.
Nouns, adjectives and pronouns are nomines. In Finnish they behave alike, that's why they are introduced under same chapter.
Finnish syntax, how to form correct sentences.
Derivation
Derivation is a typical way of word formation.