For a start you are using the wrong terminology, Cloning is for when you want to move your OS to a larger drive, and then keep that larger drive as you main C: drive - usually physically swapping the drives after cloning, then keeping the original drive as spare capacity.
What you want to do, as I understand it, is to Backup your Main C: drive on to a separate drive in the caddy. This is the correct way to do it.
What you should do is Backup Your OS C: plus your Documents Data F: This will result in one Image which you would save to your external drive.
It is pretty straightforward, just choose to backup and save as above, using all the Default settings of Acronis. Don't try altering anything, just let it do its own thing. It is not even necessary to give your Backup a Name or a Password (I never do).
Remember to Validate your Backup once completed.