So I am completely new with road bikes and barely know what I'm searching for half the time.

Recently I've purchased a road bike off amazon(the Vilano Aluminum 21 speed) and had no idea that the gear shifters that I wanted, which are the sti gear shifters, were not on it and rather they had Shimano A050. Mainly because I didn't know what I was searching for but but I knew what I wanted.

Currently, I'm trying to find sti gear shifter for a 3x7 bike but want something more modern than the shimano rsx sti. I've also read about using an 8-speed shifter by creating a "phantom gear" but am unsure on how that works.

All help is appreciated. Thanks