Hook up the wires as follows:
red to black
black to black
green to bare
Doesn't matter which black you use for red to black.
If the supply ends are aluminum wire and the stove is copper, you'll need to employ COPALUM connectors to prevent issues related to joining dissimilar metals (ask at the big box store) for the correct connectors and be sure to follow the installation instructions with these connectors.
There should be a box in the unit where these connections can be tucked away with a cover plate to enclose. Otherwise, buy your self a 4"x4" J-box w/cover plate and cable connectors for your own enclosure.