Can anyone explain me the genitive case better?

[Erica.21]

I've got which articles I have to use but I haven't got how the other words change at the end

[relox84]

I'm not a native speaker but here's what i understand of the genitive case endings:

In the singular:

-neuter nouns take the -ου ending

-ος becomes -ου

-ης/-ες become -η/-ε (masculine)

-η/-α become -ης/-ας (feminine)

In the plural: all nouns take the -ων ending

[mizinamo]

Neuter -ου: true for neuters in -ο and -ι.

Neuters in -μα turn into -ματος (e.g. του μαθήματος "of the lesson").

[jaye16]

In the Tips & notes (found at the top left of the page) there is an explanation of the Genitive with examples.

For a real in-depth grammar review see here