Oil sending unit issues????

Today I hooked up my temp sending unit. Went to do the sending unit for the oil pressure, and one I cant figure out how to remove the old sending unit, and two, where the heck is the plug for the new one? My sending unit thats on there for the idiot light has one electrical connection sticking out from it, but the new sending unit has a connection similar to the other weatherproof connections under the hood. I could not locate any other loose hookups on that side of the motor that might be it? Did I screw up when I bought the sending unit?
:banghead: :banghead: :banghead: :banghead: :banghead: