You'll be able to go to the Singer website and download a manual for free as soon as you know which model 15 you have.
My guess is that it's a 15-91, and mine is in a cabinet with a kneebar, BUT! all the kneebar does is push on the foot feed for you. The foot feed is inside the cabinet in a clamp.
Class 15 bobbins are what you want for your new girl, and short shank attachments. Sew Classic should have the bobbins, and the attachments, but I'd look at the thrift/antique stores for the attachments and get originals. (They're usually cheaper too!
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Congrats! You sound very excited, do you have pics yet?