Applications for SAMI observing time can be for either visitor or service mode.
See Applying for time on the AAT for more information on the application process.
Observations with SAMI require fields in which there are 13 science objects (which may include a secondary standard) and at least 1 guide star. SAMI has 3 guide bundles that plug into the plate to observe up to 3 guide stars. As each field is drilled on a plate, and plate changes cost ~ 30 minutes of observing time, programs should ideally be suited to long exposures of several hours. A typical SAMI observing night would have a plate put in at the start of the night, and either observed for the whole night, or changed for a second plate in the middle of night (or second field on the same plate). Short exposure times are therefore less efficient. The observer needs to supply standard and guide stars for their science field.
Two useful resources in preparing a proposal are:
Exposure Time Calculator Estimate exposure times or signal-to-noise for SAMI observations, and
AAOmega grating calculator provides information on expected wavelength coverage and resolution for a particular configuration of the spectrograph.