How is the best way to install my SSD and sata drives

Well, it seems like common wisdom is to put your OS on the SSD drive. If you just put that there, then the 250GB should be plenty.
 
I'd make the 1TB internal drives for audio and samples respectively. Actually I'd consider dumping the USB drives and/or those and moving up to at least 2TB drives. Better yet get three of them: one for audio, one for samples and virtual instrument data folders, and the third for internal backup.

Ig you are filling up a 250 GB SSD, then you almost certainly have things on there beyond the OS and applications.
 
I have a 120 GB SSD that only has Windows and all applications on it, and I still have 60-70 GB left on it, and could further tweak it if needed.
 
I DID alter the 'Location' of my various user folders (documents, pictures, downloads, etc...) to live on a second hard drive - I did it with alter Properties, using the Location tab.  Some folks use mlink to do it, but I never bothered doing that (though it works fine for them).
 
Also, take great care when installing synths with large sample libraries, to make sure you control placement of those libraries to be installed on any other drive than your SSD with the OS on it.  As others pointed out, you likely want sample libraries to live on your largest disk drive.  There is usually an option to alter library disk placement during install of software such as Kontakt, etc.
 
Bob Bone
 

Just be mindful of where programs are caching audio/video files. A 250GB SSD for O/S and all apps is plenty. A lot of programs dump their "temp" files on the C drive as well, but audio and video files are the biggies to watch.