Fresh install for MacBook
What you need to do when you want a fresh install is to follow these steps on here:

How to create a bootable installer for macOS


and then boot from it (press and hold ⌥-Option while powering up) to install the OS.

Other then the above proceddure this formats the drive completly so I recommend to do a backup before even though you have everything in the cloud. Sorry, nevermind since you add a new SSD.

After finishing the installation keep in mind to enable TRIM since you installed a 3rd-party SSD!
Then you can copy all your needed files.