If you see stringing while printing don't worry

For easier support removal and smooth surface after support is removed.
Use "Enable Support Interface"
(If you using Cura)

I printed with PLA
With TPU it will be better and will add more protection

sample video:
https://www.youtube.com/watch?v=bbXf_YtwFjU&t=3s

NOTE: There is a tiny triangle that indicates the bottom side of the case