First, we need the basic "How to build a baseline". Mostly the explanation is pre-planned work. That holds true for a two-week sprint or a two-month phase or even a two year (predictable) project.

Then we draw our budgeted cost for the planned (scheduled) work, which we can happily call a burn-down, a burn-up or the planned value (PV).

Then we track what meets the definition of done because demonstration and testing have proved that acceptance criteria (AC) have been achieved.