There don't appear to be any teardown instructions on the web for this model. Here is what Tom's said in their review:
https
/www.tomsguide.com/us/acer-aspire-s-24,review-5365.html
Everything is in the base, and a few screws (probably on the bottom) should give you access to the insides. I would imagine they are using a 2.5" hard drive, so an SSD should swap right in.