what is the best way to move an oscar to another tank please

You mean just the moving itself? or actually the whole process of moving it from its current house to a new space?

If it's just a case of taking the oscar out of the tank and putting it in another one then the process is extremely easy, although you might get a bit of a soaking. We find it easier to net the Oscar using a large net. Put it in a bucket that has enough water to submerge it. Cover the fish over with a wet towel, this will calm it down. The manoeuvres in the other tank, wrap it in the towel and put it in the tank. Very easy process.

some people do it this way:
-removed all decor from the existing tank to avoid injury.
-lower the water level for easy catching
-use big net to scoop the fish (towel or t-shirt will also do)
-then lower the net to the other tank to release the fish slowly

keep a mop an bucket handy, or a few towels to dry the floor, as OFL said your going to get wet.))))

and the celing !!!!!!!!! LMFAO ..