Post flop plus app

Hello I have been playing for awhile now but I am not in a position to be able to use a solver. I purchased an app called post flop plus and it trains you by putting you in spots at different stack depth and asks you to choose bet size and action. I am absolutely terrible at this. I think part of it is I can't use a solver to see why a decision is better than another but it will show me range splits after the hand directly from a solver. Does anyone have any experience with this app or any advice on how to improve on the training. My ELO is - 100 LOL.