You don't really need to configure anything to use Foot--you can run it as-is.
All those commented lines in the config file are the default settings the terminal will use. If you want to change something, then you would go in and uncomment that line and set the value you would prefer to use.
As an example, the default configuration has the setting font=monospace:size=8, which is super small on my laptop screen so I have uncommented that line and changed it to font=DejaVuSansMono:size=11.
Another example would be they recently changed the default colors of the terminal (the background is kind of green, and the font colors are different), but I had grown to really like the old color scheme so I uncommented those values in ~/.config/foot/foot.ini and set them to the old values:
[colors]
alpha=1.0
foreground=dcdccc
background=111111
## Normal/regular colors (color palette 0-7)
regular0=222222 # black
regular1=cc9393 # red
regular2=7f9f7f # green
regular3=d0bf8f # yellow
regular4=6ca0a3 # blue
regular5=dc8cc3 # magenta
regular6=93e0e3 # cyan
regular7=dcdccc # white
## Bright colors (color palette 8-15)
bright0=666666 # bright black
bright1=dca3a3 # bright red
bright2=bfebbf # bright green
bright3=f0dfaf # bright yellow
bright4=8cd0d3 # bright blue
bright5=fcace3 # bright magenta
bright6=b3ffff # bright cyan
bright7=ffffff # bright white
Basically, the only options you need to configure are the ones that you wish to be different from the defaults.
I would say go ahead and start using it, and if you run into any features you don't like then read through the documentation for that feature and figure out what you need to set in the config file to get the results you want.
Here is the page for the project: