Drop your save file here.
On macOS, you should find your save file somewhere like /Users/(YOUR USERNAME)/.config/StardewValey/Saves/(YOUR NAME)_###/(YOUR NAME)_###.
For example, mine is at /Users/jlfwong/.config/StardewValue/Saves/Jamie_244353258/Jamie_2344353258.
If you can't find that directory in Finder, try opening the terminal and running open ~/.config/StarDewValley/Saves