If your D drive contains only data (no programs), then its files can be simply be copied to the new HDD when you plug it in and format/partition it.
For the C drive, which presumably has OS and programs on it, the best idea is to "migrate" the C drive to your new SSD. Most SSDs come with software to allow you to perform this migration. I am familiar with Samsung's (which are top of the line SSDs by the way) software, and it is quite easy to use. If you don't/can't use migration software, you will need to do a clean install of Windows AND all programs onto the new SSD, which is of course a real pain.