If you have your current system all tidy and set up where you want it to be, then clone it over to the new drive and do zero setup work. (Use an app like Carbon Copy Cloner. I only name this one because I'm familiar with it and use it. There are others too.)
If it's time to rebuild your system... then it's time to rebuild your system.
If you had everything including older stored projects and /or media collections on a large drive and it will not fit on the SSD, do this:
Set up the SSD with OS/apps/project workspace* and then use the HDD for data (archived projects, media, large sample libraries, etc). The app I mentioned (CCC) will let you unselect any folders you don't want to be cloned.
*'Project workspace' is the remaining space on the drive after OS/apps. Use this for your "highest performance" project audio workspace.