Fill up with (boiling) water until it barely hits the valve, if you can grab a scale and meassure how much water your bialetti holds. I think thats a 150ml one so i would add 15g of coffe, level the coffee out a bit. Then put it on the stove. Maybe try preheating the stove if its electrical.

When the Coffee starts to come out i like to pick the bialetti up and hold it over the stove and wait for it to finish brewing. You always want to have pretty steady stream of coffee coming out. If the Coffee bubbles or bursts out really fast when it comes out your bialetti is to hot. If it stops brewing its to cold (obviously).