Having got this far you have a basic working server, that does not do much. Now is the time to check that everything done so far is fully operational, so check webmin and ssh. If these are fully operational you can now administer the machine without a screen or keyboard. It is a very good idea to reboot the machine at this stage and check that it still works correctly afterwards.
I also recomend installing phpmyadmin for MySQL (the webmin MySQL support is good but phpmyadmin is better)
If you find your router DHCP is adequate, use it, otherwise now is also the time to install DHCP.