Usually, the plaster installer will have a start up procedure to follow and it is normally tied to the warranty so it is important to find out if they have a recommendation. But a traditional start up keeps the PH at the lower end of the range (~7.2) brushing the walls and bottom every day until the plaster dust is gone. The filter will clog up quickly so it is important to clean it when the pressure rises significantly (50%). However, I would not add any CH to the pool at this stage because the plaster dust will dissolve and add plenty of CH to the pool and it is likely to be more than you want.

As for chlorine and CYA, what do you normally use to chlorinate the pool? If you are using BBB, then yes, you should add CYA (enough for 30 ppm) but not directly to the pool water as it can damage the plaster surface. It is better to add it via the skimmer or let it dissolve it in a sock in front of the pool return.