Hi,
--> To already answer your last question, no you must not delete the server you are installing from the inventory
--> I don't know what VMWare license you have, but if it's a "vSphere Enterprise Plus" license, I would advise you to backup your ESXI configuration by creating a "Host Profile", otherwise effectively I I've never done it but saving its configuration is a good idea, it will save you from having to configure your esxi manually.
--> For me step 3 is not necessary. After placing your server in "Maintenance Mode" connect to your server's console (via iLO, iDRAC, ....), stop the server and start the server on the installation iso.
--> In Step 4, there is no need to delete the data, this step will be done automatically during installation. When installing the OS I also recommend the option "InstallESXI, overwrite VMFS datastore"
--> Between step 4 and 5 (Restoration or Host Profile application), you must connect to the ESXI interface and configure at least the Management IP address there.
If you have never installed an ESXI, I advise you to connect to the console of your server (via iLO, iDRAC, ...) and note the configuration there