Why CustomPress plugin did not appear at subsite under Multisite after installation it is successful

I have installed one CustomPress plugin at my multisite. I can see this plugin is installed at the Network Admin, however, I could not see this CustomPress plugin at sub domain page, it is not there.

I have also checked and clicked saved the 2 boxes regarding enabling of Content... at the setting of CustomPress plugin under Network Admin. The problem is still there : the CustomPress just does not appear at the subdomain page. Is this a problem or is this not a problem at all ?

Kindly advise. Thanks alot.

james