Форуми / Cotonti / General / Timezone question

There is no real description what to use for timezone settings...

we have:

1) datas/config.php

2) admin.php?m=config&n=edit&o=core&p=time   settings

3) user profile settings....

???

The first 2... how do i set those properly !!  (and where can i find the info needed to set it up)

Forgot to mention.... how about DST then ????