"Floating Camera" Algorithm

hi folk,

I’m sure that this subject has been posted many times and I know that it’s starting to be very bothersome for you but I couldn’t get at least simplest camera algorithm so far. I have tried to implement it by using translation/rotation etc… functions but it didn’t give me the satisfying result.

What I mean with “floating camera” algorithm is that :
with the mouse movement the end user should be able to change the viewport, with keyboard entries, say that user has pressed the upperarrow button, user should be able to move forward and with downbutton backward.

Any source - code, tutorials will be appreciated so much,
Kind Regards,