Is the dot coming from the power up of your laser? (when you connect)
If so you need to either add a pull down resistor as has been discussed many times on the forum or leave the laser off until you are connected and Grbl is booted up. The safe option is a pull down as if the PC or driver crashes, the USB is pulled out or the TTL wire breaks the laser will go full on.
@İsmail-Arslan You usually need to install the device driver on your computer and if there firmware is not already loaded you would need to install that. Then you can select the COM port and connect, it should respond with Grbl Ready if you are connected.
@jamie87 Very common bug reported with the Elekscam software, they did have a patch "fix" for it but it changes your system settings so may not be ideal. I wrote T2Laser as a replacement software and it is very reliable with many happy users, the trial is free to use so you could test your machine.
try cut plywood from poplar it is soft wood.
I succes cut 3mm on 1 time 100% power 5.5W laser speed of cut 180mm/min.
Most important is correct focused beam! chceck this video, also distance from surface is important.
@Airmaster If you use T2Laser and my Grbl 1.1e DEFAULT and still experience problems I can help, but at this time it could be due to software and/or firmware so I am unable to offer any other suggestions.
Thanks, I've added this air assist - www.thingiverse.com/thing:1688209 . It fits perfectly on the 2500mW laser and the minimal distance is about 60mm, so 80mm means 20mm from the air assist to the surface.
@HuS Yes. The small print probably says it's the input power or some such nonsense.
Here's a genuine 20W laser, you will notice it uses 2 x laser modules (both are brand new 6W diodes being over driven to achieve 10W output at a reduced lifetime but with active cooling). The price $1495.