There are several types of bat guano with different npk ratios.
It is best mixed with the dirt, although you can make a guano 'tea', but IMHO unless you are going fully organic, guano is for soil and ferts are for watering with, lol.
What is your npk on the guano?
If the first # is highest that is good for weeks 3-end of veg; mix in with soil when you are doing your transplant at 4 nodes.
If the middle # is highest that's for the final transplant into the flowering pots.
Mix it REALLY well into the soil.