First plastering attempt

[Niscars]

I have reduced the size of a door opening and will be fitting plasterboard over the stud work. I am looking for solutions to finishing off over the plasterboard and patching into the existing plaster (looks like sand / cement with thin plaster coat). I've never done any plastering but it’s only a small area (2000 x 350). Any advice on what to use, what prep and how do I stop it cracking at the join please?
Many thanks.
Niscars

 

[David J Williams]

You will need to use scrim tape on the joints. You may be better to use a one coat plaster than standard plaster as it is easy to sand smooth. Have a look on YouTube videos of drywalling these will help you