A model with several assumptions becomes difficult to compare when only some inputs are changed for each alternative. One trial might use the new attendance estimate but retain the previous duration. Calc scenarios let you name sets of cell values and apply a chosen set together.

Start with a working copy whose formulas already produce a result you understand. List every input that changes between alternatives. Keep calculated outputs out of that list: the scenario should supply assumptions to the model, not replace the model's calculations.

Capture each alternative deliberately

For a fictional workshop sheet, imagine that attendance and hours are inputs while participant-hours is their product. Select both input cells and choose Tools, Scenarios. Give the first set a specific name and a comment explaining the assumptions. The newly created scenario becomes active.

Create the next set using the same intended input coverage. For example, the first workshop could have twelve participants for two hours, while the second has eight participants for three hours. Both produce twenty-four participant-hours, although their operational arrangements differ.

Use the Navigator's Scenarios view to inspect names and comments. Double-click a scenario to apply it. A name such as Smaller group, longer session is more informative than Final2 when another person needs to understand why the inputs changed.

Verify the inputs as well as the total

Switch from the first scenario to the second and back again. Read both input cells on every switch. In the example, looking only at the output would miss a failed or incomplete switch because the two products happen to match.

Check that unrelated inputs remain unchanged and that dependent formulas still exist. If one assumption was omitted from the selected range, correct the scenario definition before comparing a larger set of alternatives.

Record which scenario is active when issuing a result. A scenario name documents a chosen input set; it does not make those assumptions measured facts. Keep the source or rationale for each assumption alongside the workbook so the next reader can assess the comparison rather than simply choosing the most attractive output.

Reference: LibreOffice documentation.