We've been using this recipe for probably 50 years, and my family love
it.
3 pounds steak, cut about 1 1/2 inches thick. Freeze for a short time to
make cutting it thin easier. I have and use an electric slicer. Put the
steak in a zip top bag. Pour over this marinade.

1 T. salt
1 tsp onion salt
1/2 tsp pepper
1/3 cup worchestershire sauce
1/4 cup soy sauce

Marinade at least 12 hours. Lay the strips singly on cookie sheets and
put into a 150 degree oven. Leave over night , turning occasionally, or
until dried the way you want. I have a convection oven so it does dry
out quicker that it used to in the regular oven.