How to configure the postgresql.conf files

Hello all!
I'm a new to Postgresql , I have never used it before.
I am having an issue with configure the postgresql.conf file.
The machine itself is a
CPU= 2.66GHz P4 w/
Memory= 2G
Maybe you can tell me how to configure these parameters.
shared_buffers=
max_fsm_relations=
max_fsm_pages=
max_locks_per_transaction=
wal_buffers=
sort_mem=
vacuum_mem=
wal_files=
wal_sync_method=
wal_debug =
commit_delay =
commit_siblings =
checkpoint_segments =
checkpoint_timeout =
fsync = true
enable_seqscan =
enable_indexscan =
enable_tidscan =
enable_sort =
enable_nestloop =
enable_mergejoin =
enable_hashjoin =
ksqo =
effective_cache_size =
random_page_cost =
cpu_tuple_cost =
cpu_index_tuple_cost =
cpu_operator_cost =

Would you mind to send me a copy of examples .(postgresql.conf)
Thanks
Sincerely,

Chris.Wu