Present continues:
He is walking his dog now
present perfect:
he have walked dog already
past simple:
he walked his dog yesterday
past continuous:
he was walking his dog all day long
past perfect:
he had walked his dog by time you come
future
he will walk his dog tomorrow
future continues
he will be walking his dog tomorrow at 5 p.m.
future perfect:
he will have walked his dog by time you come