If you want to marinade steak, give the paste and the meat into a freezer bag and store at room temperature for 2 hours or in the fridge for 4 hours.
Remove all the marinade from the meat and give it to a very hot frying pan with a little oil in it and fry from both sides until crisp
Either reduce the heat now and let the meat set in the pan for a few minutes or give it to the oven and let it set there. No matter where you decide to let the meat cook, add the remaining marinade and fully cover the meat with it.
For steak sandwiches I recommend to cut finer stripes as it's easier to eat this way.