Before you turn on your PS4 with its new hard drive, you will need to download the latest operating system onto a USB flash drive. Download it on your PC from their website, move it to the flash drive, and then insert the flash drive into the PS4.
To install the OS from the flash drive, turn on the PS4 in safe mode. Hold down the power button for seven seconds to power up safe mode. Plug in your PS4 controller to the console (wireless is disabled), and then follow the on-screen prompts.
Lastly, after the OS is installed and raring to go, it's time to upload your user data, game saves, etc. by restoring from your backup. Isn't it great our Help Desk has that info too?