i got a Vilano(i know, i know) from ebay and it got shipped here today, i put it together and changed all the parts out for better things but im having a problem with the headset, my old bike (dawes SST) all i had to do was take out the middle screw with an allen key and either push it up or down depending on how high or low i want the handlebar height... on this there are 3 cones and i thought well maybe if i take one out it will lower it? didnt work the headset was unstable even when screwed in fully. My last headset was threadless and i could adjust it, is it just this bike? lil help please thanks

Edit: im actually trying to lower the stem? my handlebars are up too high and my frame slopes twords the back wheel downwards so my seat has to be extra high yet my feet cant touch the pedals, its all strange ha i just want the handle bars lower on the headset is this impossible?