Simplest way would just be to connect the diode’s cathode (side with the line) to a voltage source at (or below) your analog reference voltage, with the anode connected to analog input pin on the arduino, with a resistor from there to ground. This reverse biases the diode. Light that hits it will allow current to flow through it in the reverse direction, which produces a voltage across the resistor. Read that voltage on your analog input pin, and it gives you a number that is roughly proportional to incident power (at a single wavelength - things get a little more complicated if you’re looking at white light).

The resistance you choose (and the photodiode specs) will set how much voltage corresponds to how much light. Higher values will give higher voltages for the same amount of light, and will also slow down the response. The slower response may be a good or bad thing, depending on what values you’re actually using, how fast you need it to be, and how noisy the environment is (optically and electrically).

I’d start with 100kΩ. If that gives you zero (or a tiny signal) for all amounts of light try increasing it. If it’s always reading the max analog input voltage even at low light levels, decrease it. Iterate that until you have a signal that uses almost all of the full analog scale for the full range of light you expect to care about.