When the destination for your ESXi has been chosen, you should decide what method to use for the ESXi deployment. Before proceeding with the installation, you can download the installation files at URL https://my.vmware.com/web/vmware/downloads/. The installation files are typically provided in ISO format to be easily burned to a physical CD/DVD or mounted to a server.
The installation using a physical CD/DVD can be considered old-fashioned and time-consuming, but to install the ESXi, you have also the option of using an USB flash drive, through the network using the Preboot Execution Environment (PXE) or mounting the ISO installation file (virtual CD) if your server is equipped with the remote management tool (iLO, iDRAC, IPMI, or similar). Perhaps the USB key is the fastest solution to use if your server doesn't have any integrated remote management tool since you just need to create a bootable USB key. Tools such as UNETbootin or Rufus can do that using the ISO file without burning any CDs:
Some manufacturers, such as HP, Dell, and Super Micro provide servers with an integrated remote management tool that allows the use of the virtual CD feature that remains a good way to install your ESXi without the need to burn the ISO (you can sit at your desk without getting cold inside the data center):
Another option could be booting from the SAN (for FC storage, but it also works for FCoE and, in some cases, for iSCSI). You can deploy one ESXi on a 1 GB LUN of the storage, then stop the reboot process after the installation. At this point, you have a generalized installation of the ESXi. You just make several copies of this LUN from the SAN and then you have lots of ESXis ready (to be configured) with just one installation.
To avoid the risk of overwriting production data, disconnect all storage devices connected to the physical server you are not using as destinations for installing the ESXi.
Let's examine the three possible installation options: