First you need to know why you want to setup a communist party
in Singapore.
And then evaluate whether your goals and visions are already
incorporated in the existing political party of PAP.
I myself have the view that PAP is already taking some communist
teachings.
Perhaps you can elaborate more specifically what kind of
'communism' or 'communist party' that you want to achieve.
In China, officially there is a communist party but they are
implementing semi-capitalism.
Again, you need to find what exactly you want to achieve. You want
less rich-poor divide? You want no religions? Centralized
government planning? Free public goods like education/ housing/
transport? Perhaps you have some specific points you wish to
realize and other points you do not like, and the 'party' that you
imagine might not be called 'Communist Party' after all.