can someone give the steps to do a water knot for like a harness

Here you go, follow this link:
http://indoorclimbing.com/Water_Knot.html

A water knot is just a regular overhand knot - just like the one used to tie a shoelace (without the loops) or fabric belt.

For climbing, this usually implies that there is a ''follow through'' of the other end (like the previous answer shows). There is a very good book of climbing knots by John Long - l would suggest every climber read it.

IF YOU ARE GOING TO TRUST YOUR LIFE TO A WATER KNOT, **PLEASE** LEARN HOW TO TIE A DOUBLE FISHERMAN BACKUP ON EACH SIDE.

Good Luck