It looks like you already have windows installed to the Western Digital drive.
You can't just install an SSD and have windows boot to it, you have to install windows to it somehow.
At this point its probably worthwhile to clone the WD to the SSD. This will copy the windows & everything over to the SSD and make it bootable.
You, of course, have the option of installing a fresh new windows to the SSD if you feel that is best.