i386 apps in x86_64 envirinment

[don fisher]

I am converting from Fedora, so please pardon any indiscretions.

I attempted to install the Adobe acrobat .deb package from adobe.com. 
There were libraries that were not available. In Fedora, one could 
install both 32 bit and 64 bit environments. The RPM names and yum 
descriptions contained the architecture description.

How does one add the 32 bit environment to a 64 bit ubuntu install? 
Along similar lines, how does one install both the Gnome and KDE on the 
same system. Reviewing the packages listed by synaptic, there are many 
core KDE packages that I am missing.

Thanks in advance for your assistance.

don