The settings for declumping are within the IdentifyPrimaryObjects module, to access them you’ll need to enable “Use advanced settings”.
There are a variety of options for this part of the process, but you may want to experiment with changing the size of the declumping smoothing filter to start with. It’s worth keeping in mind that such automated analysis will never be perfect, so you might expect the occasional cell which is split in two, or pair of cells which are joined together incorrectly. You might want to take a look at this blog post for further guidance on what to aim for.
Hope that helps!