It's try-and-error / find out what film you like.
You can also check flickr for example and search the pool for photos shot with this or that film to get an idea.
Maybe just start with Kodak Portra 160..
Not the biggest Ektar fan myself to be honest as colours / saturation looks "too crazy" for me, but really enjoyed some pictures shot with this on overcast / cloudy days I saw recently.
It's try-and-error / find out what film you like.
You can also check flickr for example and search the pool for photos shot with this or that film to get an idea.
Maybe just start with Kodak Portra 160..