In the Early-stage as you've mentioned we absorb Qi from Qi stone and store it within our dantian which is just below your belly button. Once you can store Qi in your dantian means you've reached the Early stage.
To reach Mid-stage you just have to fill your dantian with Qi. Once it has reached its full potential means you're in the Mid-stage of Qi training. Till now Qi is in a gaseous state.
Then to reach the High stage you have to create a single drop of liquid Qi in your dantian.
And to reach Peak one has to turn all the gaseous Qi in their dantian to liquid and absorb more Qi and turn it into liquid till your dantian becomes full.' Arthur patiently explained all of this. One needs to have a clear vision of where the destination is to take the correct paths.
"So I'm currently high-level of qi training stage, as I've produced a single drop in my dantian."