Welcome; we'll try to answer your questions as best we can. The more information you provide, the better our responses will be.
So let's talk watering... Roses need moist, well-drained soil and occasional fertilizing with a balanced fertilizer. You should water them frequently enough to keep the soil moist, but not continuously wet. It's OK for the soil to dry out a little bit between waterings.
Now let's consider sunlight. Most roses need 6 hours of direct sunlight, and I wonder if it's getting enough sun on your balcony. Bright shade is not normally sufficient.
And now let's consider the pot. I suspect Jerri will chime in here soon about growing roses in pots - i.e., the right sized pot for the rose given its size and its root mass, proper drainage holes, etc. The pot you have looks tall and narrow, which I don't think will be optimum. I think ultimately you will want something wider, and not as tall.
Edited to add: It looks like you've posted this same post to another thread here in the rose forum, which explains why the first sentence in your post puzzled me at first.
