1) Design and Print out the mask with a laser printer on a glossy sheet of paper. As you turn the sheet upside down, the print should be mirrored. Check for alignment when both sides are to be used.
2) Use a hot iron to transfer the toner black onto the cupper board. Select the highest temperature available.
4) Do some corrections to the mask. During the etching the toner will cover the cupper. Uncovered areas will disappear.
5) Etch your PCB with suitable chemical, like Iron(III) chloride (FeCl3) or Sodium persulfate (Na2S2O8). Take a hot plate to Keep a warm temperature.
7) Drill holes, solder devices and cover with transparent lacquer to prevent corrosion of cupper.