Measured up my battery and figured out how I'm gonna mount it, then transfered it all onto the sheet metal
Cut it all out with an angle grinder with a cut off wheel. Then marked it for some speed holes.
Drilled out speed holes
Dusted it off and scored some lines with the angle grinder where the sides will be formed. This helps ya get some nice clean bends.
Bent all the sides up and squared it off and tacked it. Checked it again for square and finally welded all the corners.