I don't have a fuse diagram for many of the vehicles I work on but I do use a good light up under the dash and read what the different fuses say they control. I think most fuse boxes are set up this way. The worst I have seen is on an old U-Haul truck I drive a lot. Numbers only and since it is 1989 vintage it was go check the internet for what I could find. Most had pdfs for the gas engine that was in that truck but few had the diesel I needed. So what to do?
Start pulling each one to figure it out. I have a good volt/ohm meter and I could tell if I had 12 volts with the switch off or on. You should be able to do the same. I would start with the smaller numbered ones, the 5 and 7.5 amp are likely to control the cigarette lighter or it might be called a power port now. The radio was wired into those fuses or actually the fuse box said radio but also had the lighter tied to it.
So it should not be hard to figure out and you might even find that there are fuses missing in the box that are controlled by the ignition switch and can just run the wire to them and put a fuse in where it fits and call it done. I did that on my Ford Ranger for a light in the canopy. So nice of them to think ahead for me.
Good luck. Should be a 5 min operation if you have a good meter. Otherwise you will have to put something in the lighter like a cell charger with a light on it and start pulling fuses. Again a 10 min operation max.