First, it is never a good idea to use unknown steel when heat treating will be needed. Different steels require different heat treats, and you risk losing your time and efforts.
However, Since it is done, take the safest route.
Heat to red-orange in dim light, hold that heat for a minute or so, then quench in a gallon of vege cooking oil that is warmed to about 130°. Two gallons would be better. Once the blade is in the oil, move it fore and aft, or up and down. Keep it in the oil for at least a half minute, or a 30 count.
Once at room temp, see if you can cut the edge with a good file. If not, you succeeded. Then temper in your kitchen oven for two one hour heats at 400°. Quench in water after each temper. DO NOT trust the temp setting of your oven. Use a separate oven thermometer, and have the oven pre-heated before putting the blade in.