Print out the diagram from the software's File menu. Print it out on a glossy paper, such as magazine paper. You should ensure the circuit is mirrored before doing that (most PCB layout programs have this as an option when printing). Once printed, make sure you don’t touch the ink part on the paper as it can get on your hands.
Align the circuit diagram on the paper with the circuit board (the diagram should be facing the copper part of the circuit board).
Slowing start taking off the paper and soon all of the paper should come off. If certain areas seem particularly difficult to peel off, you can try soaking a bit more. If everything went well, you will have a copper board with your PCB pads and signal lines traced out in black toner.
Etch the board using one of the methods below. This process removes any unnecessary copper from the board leaving only wiring of the final circuit.
Prepare the acid etchant. For example, some crystallized acids require being dissolved in hot water
Submerge the board in the acid.
Make sure to stir every 15-20 minutes.
Take the board out and wash it when all unnecessary copper is etched away from the board.
The further steps to follow are described in the acid etching method specific steps 3 to 7.