Denis, Hi. It's dead easy with a half decent tuner.
Tune all the strings, give them a bend, pull, stretch - tune again.
On "G"
gently fret the 12th (G an octave up - obviously) and on the tuner, that
should also be a "G" (double check open "G")
If the octave is "Flat", move the saddle towards the neck, if it is sharp - go the other way. Do "D" "A" and "E" and then check them all again, just to make sure.
This is on the basis that you are happy with the action. If you lower it, your adjustments will be "Flat", if you raise it, the octave will become "Sharp"
Takes me about 10 - 15 mins to do - you can't go wrong.
You can double check - e.g the 5th on "G" should be "C", exactly!
The 7th on the "D" would be "A" etc, etc.
Have a go - let me know how you get on.
Cheers.