For the exercise I am creating a barn setting. I’m making a gate and beveled the side to give it plank shapes but I also want to create a square section which will be extruded inwards to become a handle/lock. What would be the good tool for this? I’m thinking maybe the knife tool but but I’m wondering if there is another tool I can use to get the dimensions correct.
Thanks for your help.
Model (red box is what I want):

Reference:
