Linux SA work - Installation of generic Proxy Server and atmail server

I have a rented VPS (Virtual Private Server) that runs CentOS and would like someone to install a proxy server and atmail server for which I have bought the webmail license for. I estimate this work will take a maximum of 2 days to finish. I have all the settings and software can be downloaded from internet as well. The winning bidder will be given an account on the Linux server from which to setup and configure the software. Guidance can be given but the bidder is expected to do the research themselves and ask the server's root administrator to carry out operations not allowed as the non-priviliged username they will get. (copy files/start services/give root commands) This whole setup needs to be done so that a small company will enable users to use webmail from the rented Linux server and control/monitor employee use of the web.