Every persistent indicator (reporting, boolean, choice, factor) is assigned to applicable structure nodes.
For instance, a reporting indicator to be reported on the site level will have one assignment for each site per reporting period. The assignment can be used to control activation of non-mandatory indicators (does the site need to report this value?), and also whether the value shall be open for editing. This means that you control editing on specific combinations of indicators and structures, without changeing access permissions.
Depending on the indicator type, you perform additional configuration such as which input unit is to be used, or which input frequency (note the difference between input and reporting units and frequencies).