The special case with a VPS
in most cases a VPS has only one virtual drive attached, what makes it impossible (if the VPS uses LVM) for Proxmox to create a template, since the template needs to be on another Storage (correct me, if it changed in meantime). So what you do instead is download a LXC Template from the GUI, assign it the last possible IP you have and costumize it. This has several advantages:
the first Container has the id 0, if it's your template, the first Container can be assigned with your IP X.X.X.1 you can simply clone your fist Container via GUI even tough it's no "real" Template
Note: This is more or less a workaround, since if you have f.e. ZFS as storage, you CAN create templates. Netherless, it is good practice to use your first created container / VM as template, since it's easier, to assign your IP addresses in order.