YouTube it. Look at lots of jobs. But a soldering iron or wood burning kit. Practice on some PMAGs or other unused polymer gun accessories. Then do it yourself. Start with light, brief indentations. Stick to small areas when you start and outline your desired area. Then fill it in. Careful on the backstrap I the highest point of the grip. Aggressive stippling there can grab cover clothing if you carry concealed. If you do small areas and work outward to larger areas but you can't go back and remove stippling easily.
In the picture above, the 17 has a chopped grip to take 19 mags and the stippling is aggressive and covers most of the grip. It is primarily a range/competition gun.
The 19 has shallower stippling and you can see that area were avoided where cover clothing may rub High points on the grip when carried concealed.