Prepare new Plaster

Personally i would take that back and just buy a contract matt and dilute with water 50/50. Then once dry i would fill any defects.

You won’t find many professional firms using these types of products. They sound the part but unnecessary. A cheap contract Matt from B&q (like the above poster said) will cost half the price for twice the volume and is just as good. Water it down roughly 50/50 and give a really good mix. Let it dry completely before adding the top coats. Spend the savings you made on a quality trade top coat for the ideal finish. Be prepared for a lot of spray when mist coating, its a messy job so get sheets down..and a hat on! The mist coat helps to highlight any dings in the wall and it’s easy to give it a fill after and spot prime them before getting on with the top coats. Hope this helps.

Just looked up the paint you have, looks like some kind of adhesion primer. So i would say unsuitable for new plaster. Use 'paint for new plaster' or a contract matt. Regarding dilutions, i wouldn't quote ratios here or anywhere else. Follow the instructions on the tub, and you are looking for a consistency where the paint is readily absorbed by the plaster. And as i always advocate, don't pick paint up off the shelf in a diy store, if you want advice about product selection, and want to get the job done right, find a good local decorating supply shop and go and have a chat with them.

As a Plasterer & Decorator I advise complete the plastering first, there's no point in sealing the walls twice when you patch up, also Screwfix sell a direct to plaster paint that is reasonable cheap if you have doubts but I also agree with previous answers use a contract matt and dilute 50/50 you should have a fairly drama free experience then 👍 All the best.