To create a sheet of metal bent on edge, there is no need to make a sketch. You click on the function and then on the edge or you want to put the fold and the part must already be a sheet metal piece.
You click on the 1st folded sheet metal function on edge and you delete it, then you make a second one and rework it, then you re-activate the 1st one.
Yes when you are in function you have the length of the sheet folded where there is blind you expand and select up to the top and there select the top at the end of the stop at the bottom
Or you do as before; Edit the sketch of your fold and you dimension from the corner of your sketch to the front by putting a dimension of 0.5 so that they don't touch each other.