@Computer_Commando - I believe the OP means that he doesn't have enough free disk space to do the upgrade directly on his computer.
@OP - As to where you should install Windows on that machine, if it were my machine, I would delete all of the existing partitions and tell Windows to install to the unallocated space on the drive. Windows would then create and format the partitions it requires during install. The drawback to this is that you would lose your recovery partition. If you are doing a clean install of Windows 10 the recovery partition is of no use anyway so you might as well recover that disk space.
However, since you have a recovery partition and you say that you want to "restore my original version of Windows 10", why not use the recovery procedure the mfr built-in to the machine to do the restore? If you install Windows 10 from the MS site, you will get a vanilla version of Windows 10 with none of the drivers and software supplied by the mfr for that machine. It may be a good option but you should at least think about that before you proceed.
If you wish to use the mfr's recovery procedure, you'll need to look in the manual for how to invoke it or go to the mfr's website for that info. Or, if you provide details as to the make/model of the computer someone here may be able to tell you how to do it.