Old plaster against new plasterboard

[JamesRookie78]

Hi all, I'm relative new to plastering and was wondering whether you could give some tips. The wall in question is shown in the picture. What would be best approach for this? Would you bond the new plasterboard to bring it level with old plaster and then skim the whole wall? Or would you skim twice? Thank you

 

[JessThePlasterer]

Bond it. It won’t take you long to do

 

[Lastlaff]

It’s your door-lining your working too.

 

[Stewie03]

Sort your ceiling line out afterwards aswell

 

[JamesRookie78]

Was only my third ceiling but yes I should have made it cleaner