Nothing special really needs to be done.
I would format it as a single large partition.
Use disk management under administrative tools to do the job.
Move whatever data you want to it.
For games and apps, you will usually need to reinstall them. Installs will ask you where the install should be done. The default will usually be the "C" drive, but you can change that.
You can use windows easy transfer to copy all of your files and settings to the external drive.
After you install windows on the ssd, you can import those files and settings, individually, ot totally.