USAFRet is right, of course. It sounds like you plan to do a fresh install of Win 7 on it. Then, of course, you will have to install new application software. You MAY have old files on an old HDD that you want to copy to your new system - you have not said anything about that.
I suggest this sequence.
1. Install the new SSD in your system as the ONLY "drive" installed in your system (except that you might have an optical disk drive that can be left installed). Install Windows to that. At this point, consider this. Windows 7 will be end-of-life soon, and I believe you can arrange to replace / update that for free with Windows 10. So look into the details of that. Right after getting Win 7 installed is the best time to change to Win 10 if you want to.
2. After Windows (whichever) is fully installed on your SSD, shut down and install the new 4 TB HDD. Boot up and use Windows Disk Management to find that new HDD in its lower areas. It will not be shown as a drive ready to use. Instead it will show as one large blank Unallocated Space. RIGHT-click on that and choose to Create a New Simple Volume. Look closely at the settings it proposes to use. You will want to specify that it uses the new GPT (or GUID) system for this (NOT the older MBR) and that is uses all of the 4 TB of space for a single large volume. You should specify that this is NOT a BOOTABLE drive. Most other options will be set correctly. When you're satisfied, let it run that process. If you let it do a Full Format (usually the default setting) it will take a LONG time, so just be patient. When it's done, back out and reboot into BIOS Setup. Check the Boot Priority Sequence to ensure it is set the way you want, then SAVE and EXIT to save the settings and reboot. The 4TB unit should show up now in Windows Explorer.
3. In Windows you can specify where several default file folders are placed, such as My Photos, all your application software, My Documents, etc. By default they are on the C: drive, which is your SSD. You may want to change some of those to the large HDD.
4, Now you can start installing your application software. As each is set up you normally have an option to specify which drive it will be placed on, and you may want to put some or all on the HDD. Once an app is installed, it is common within that app to have the option to specify where that app will store the data files it creates, and you can customize each app that way.
5. IF you have old files on an old HDD, you can connect that into the system (even if only temporarily) and copy what you want to the locations you have established in the new SSD and 4 TB HDD.
Thanks for Best Solution. Have fun!