I finaly got it . Almost.

When it is rising, it is actively feeding.  When the rise stops or recedes, the feeding has reduced or stopped.  At room temp it will need to be fed every 24 hours.  In the fridge, it should be brought to room temp and then fed.  I do mine about every three weeks.  Most people like using the starter at about the peak of its rise and before the rise recedes.

Good luck and good smoking!

Yes and no.  Actually you have to know how your starter acts and know its progression in the feeding process.  Ideal is to catch it a little bit before it reaches its full feeding frenzy, but if you catch it at the top, it will still work if the starter itself is strong enough.  There are strong starters and weak starters.  That is why many people still add yeast when making sourdough bread.  It will take some practice and experimentation.  You will get it with time. 

Good luck and good smoking!