You must burn the ISO file to a CDROM with NERO for example.
Next, boot on the CD. And follow the instructions.
At reboot, login you with the account root and look at the IP address.
Like that, you can connect you on the server by a web browser like IE or FireFox.
Please, read the document Elastix Without Tears before to install and put some parameters,.
You must have a free station. Be careful if you have Windows into your station and if you don't know Linux.
The best, install VirualBox (for example) with a bridge access on Ethernet device, and put install Elastix into a virtual machine to make some test.
Yes be very careful, this is not a desktop program that just runs with a click of your Icon on an Windows OS, its a server and there is a years worth of learning before you even become comfortable and familiar with the system. There is a ton of support and friendly people on here so you chose the right one. Just read elastix without tears first and search the hell out of google before you ask here, that works for me. Good Luck.