You may need to look up or find out some of the information ahead of time. If you are not using a common photometric system, you will need to supply the central wavelengths and widths of the passbands you are using. Even if you are using a common system, information on your actual instrumental passbands will be helpful, if it is available. If you get halfway through and discover you lack some vital piece of information, just enter Q to quit. Get what you need, and begin again.
Star coordinates are needed to a minute of arc or better for accurate data reduction, so you may as well supply accurate coordinates for planning, too. A few files of standard stars are already available.
If you are doing pulse-counting photometry, the uncertainty in the pulse-overlap correction sets a limit to the brightest stars that can be used as standards. Therefore, you will need to have both the effective dead-time of your system, and a realistic estimate of its uncertainty.