Before starting to enter exposure details, it is worth considering how XRPS will handle entries internally. Within an observation, a subdirectory is opened for each exposure. For each of the XMM science instruments at least one exposure must be specified. The suggested order (as mentioned already in § 4.7) is
Thus, the recommended sequence of steps to fill out the exposure details for an observation, using the top row of functional keys at the bottom of the observation details page, is to first proceed to ``Add EPIC MOS'' and, once finished with all EPIC MOS-1 and EPIC MOS-2 exposures, to ``Add EPIC pn'', before going to ``Add RGS'' and ``Add OM'', as often as necessary to fill in all required exposures (see the following paragraphs). Alternatively, a functional button at the bottom of each exposure page can be used to copy exposures. Also at the bottom of the page there is a button to delete each exposure again.
XRPS will count all exposures belonging to one observation consecutively. The name of the instrument for which an exposure has been defined will be part of the file name visible in the navigation tool.