Threading for BB (British) for Hollowtech 2 or square taper crankset?
The normal threaded, road, Hollowtech II B.B. is designed to fit in a regular 68mm British threaded B.B. shell just like a square taper cartridge B.B.  so there is no difference in the threading (1.37x24TPI)

So if you have a 68mm wide threaded shell, the B.B. should go straight in and you can install a Hollowtech II crankset. It’s something I’ve done on one of my bikes. 

The difference with PressFit is that the frame does not have any threads in the B.B. shell. Bearings are then pressed into the frame instead and the tight fit holds them in place - so not compatible with a threaded frame. There are lots of slightly different sizes of PressFit bearings, which you could read about, but luckily you probably don’t need to