Can I replace my battery with no battery screws?

I had to take my MacBook to the Apple store a month ago as the battery was swollen. Apple took the swollen battery out for me and told me to buy a replacement online as Apple no longer sells batteries for this model (note the rest of the MacBook has been rebuilt inside so I don’t want to get a new one).

I ordered a battery online but when I took the MacBook apart it seems the Apple took the screws that hold the battery in place. The replacement kit comes with screwdrivers but no screws.

I am confused, do I need to screw the replacement battery in place or is it fine just being held in place by the case?

thanks !

Lisa