it's almost same as Ubuntu here you can follow these steps

Install and configure the database server, PostgreSQL

sudo apt-get install postgresql

Then configure the OpenERP user on postgres:

First change to the postgres user so we have the necessary privileges to configure the database.

sudo su - postgres

Now create a new database user. This is so OpenERP has access rights to connect to PostgreSQL and to create and drop databases. Remember what your choice of password is here; you will need it later on:

createuser --createdb --username postgres --no-createrole --no-superuser --pwprompt openerp
Enter password for new role:
* Enter it again: *

Finally exit from the postgres user account:

exit

Install the necessary Python libraries for the server

sudo apt-get install python-dateutil python-docutils python-feedparser python-gdata \ python-jinja2 python-ldap python-libxslt1 python-lxml python-mako python-mock python-openid \ python-psycopg2 python-psutil python-pybabel python-pychart python-pydot python-pyparsing \ python-reportlab python-simplejson python-tz python-unittest2 python-vatnumber python-vobject \ python-webdav python-werkzeug python-xlwt python-yaml python-zsi

Download Openerp Server

and extract the file than run the openerp-server