You probably should partition your big drive so that there are 3 partitions. The first where boot files are kept which would be called the system partition (100 MB size) and set as the active partition too. The second should be also a primary partition where you can have Windows and programs installed to, known as the boot partition (200-300 GB in size, as you wish) and the third partition also primary where you can move all the data on it now to be kept.
When done, you can format the small drive then use it as your temp folder drive and pagefile drive.
You can do a clone from boot partition and system partition of your current small C drive to the correct partitions on the big drive, when the big drive is ready.
Acronis Disk Director is good to use for this.
But, lots also depends on your bios - if it is UEFI or not.
We can best help advise about it, if interested in doing something like this, if you post a screenshot of your current Disk Management screen.