there is no real easy way.....
search CS for 5 cent test on the dosing of the basket so you leave the impression of the "screw" of the group head in your coffee puck but not that it rips a big hole in it.
by taking notice of how much you have then "dosed" to get this right you can then work on the grind / tamp.
if you keep your tamp / dose consistent while adjusting grind you can get to the right pour.
you can then, grind finer / tamp lighter or grind coarser / tamp harder looking for the shot that tastes the best to you.
be prepared to buy a few KGs of beans to get into the swing of things.
you might also want to consider reading about temp surfing the Silva aiming for temp stability in your shots as well.
there has not been many posts about this of late.......