Replacing drive should never really be a problem. Adding drive can be.
Check this video: https://www.youtube.com/watch?v=Spldop-OLtY&ab_channel=BrueComputing
You can download a free version "Acronis WD Edition" from WD's website. Prerequisite: at least 1 hard disk from WD must be recognised in the system. Cloning is easy if the new SSD has the same size as the HDD. Otherwise, you should clean up the HDD to the size of the SSD.
necessary tools?
You need a Sata cable SATA II cable (50cm)
and a free space in the case. Screws are included.
Depending on the case, you may also need a mounting frame.
Corsair SSD 2.5" to 3.5" mounting frame
If you want to use the new SSD as a boot drive, you may need software to clone the existing one.