Autos are really not for beginners, you are far better off growing normal photoperiod fems.........you will learn a lot more and they are far more forgiving of any small errors and you also get to decide when flowering occurs and only when you are satisfied with the plants development rather than autos which flower whenever they chose, whereby you run the risk of waiting 6-10 weeks fo dwarf plants to mature their flowers.
In my opinion, the only advantage to autos is that you do not have to alter the light timer, otherwise autos do not offer anything above what can already be achieved with photoperiod fems.
When it comes to watering, it is quite simple...........water the entire pot enough so that some water comes out of the bottom of the pot, then do not water again until the top inch and a half of the soil is completely dry again, be this one day or ten days.
A quick guide as to when to harvest can easily be estimated by the condition of the flower pistils/hairs..........once there are 98-99% brown pistils, you will be entering the harvest zone.