Great question — answering as the UphillTech team:
If you wish to edit the theme files, I suggest using Shopify Theme Kit . Therefore, connecting to the existing theme and duplicate to properly create and test your edits.
Full answer by Duarte Nunes: https://stackoverflow.stackexchange.com/a/59361767 (CC BY-SA 4.0).
Need it done for your business? UphillTech.