A calculator is nice to pre-calculate the elevation in case you don't have experience with local TV sats at about the same position, to know what kind of angle (and thus obstacle clearance) you can expect.
However in my experience it is kind of useless for pointing the antenna, because the inaccuracy you get from not knowing the exact direction of south and not easily measuring the pointing direction of an offset dish is far larger than the pointing accuracy required.
So in practice it is easiest to use a TV transponder and a settopbox... and then just slowly pan around the expected direction until you find the signal, then optimize on it. A "satfinder" (a beeper that indicates the overall received signal strength) can also be helpful to find the satellite belt and then pan along it.
In Europe you can always start from a strong transponder on the Astra3 system (23.5 east) and once you have found that turn east finding the next satellite. In Northwest Europe Astra2 (28.2 east) can be used the same way.
In the past it all was far easier with analog TV than now with digital.