Mindenbrush has good advice. That's a useful chart.
However, craft paint is so cheap that you can't go wrong with just grabbing a bunch and testing it. That's what I did.
I've been using a mixture of burnt umber, brown, ochre, black and white, in varying degrees, to give me many different shades of wood color and other natural shades.
Burnt umber on its own is kind of a dark brown with reddish undertones. The draft paint I bought labeled simply "brown" is a kind of light to medium brown which mixes well with either black or white to give good alternate shades.
Plus, I've been discovering the delights of partial mixing. I'll use a big brush to put various blobs of paint on my palette, then mix them in varying strengths to give multiple shades in a single pass. I never used to do that - I was stuck on the Foundry layer method and their three-tone paint collection.
Are you French? I got my craft paint at Cultura. They are a mine for scratchbuilding and painting supplies.