First time you run injector, press new .dll then choose .dll you want to inject (example: AVA.dll) and press OK. Then simply run AVA and it'll inject. After choosing AVA.dll (example) you'll get informed that you have choosen it. Also, you'll get informed by message and beep (computer beep) when you inject hack.
Second time you run injector you can simply press "continue" and start AVA. But still you need to run as admin