dumping the schema

How to DUMP the Database schema, (so later can get it back i.e recreate everything).
I need only the schema (tables, users, groups etc..)  now (not the data, is it any different if i want the data too).

the dump should be in order so that i can just execute it...

One more thing I created db and tables with default config (with pgadmin3) i.e. owner postgres,
Now I want to switch all to other user I just created, can I do it "at once" or I
have to go and edit permission of every table...
Can I remove any access to the DB for "postgres" and "public" and leave such access to
my new user OR they should stay for some db-functionality..

tia