We used to give all the cats a bath (flea dip) regularly,,we had 6 or 7 usually. (Now that Advantage stuff takes complete care of any flea problems).
But anyway,,,2 person job.
Warm water,,
Don't run the water while you try and put the cat into it!
Fill the water and turn it off.
There's enough about this they just naturally don't like,,so any extra noises, splashing, confusion,,and they;ll be leaving immedietly.
They all hate the fact that they can't hold on to anything in the tub or sink basin,,it's slippery and smooth. So they panic. That's where you become the tree limb they use to climb free of the water trap.
We used to put a towel or two or old pair of jeans in the water and set the cat down on that. They (usually!) hung on tight to the fabric long enough to get them dunked and washed OK.
I have read where a piece of window screen in the bottom of the basin or tub does the same thing,,but have never tried that.
Anything they can craw onto with all 4, steady themselves and give them a somewhat secure feeling while in the water helps.
But if they just plain don't like the water they'll be using your arms and head as climbing posts to exit the pond.
Long sleeves and preferably a coat to protect yourself. Plenty of extra towels or other old shirts, ect to grab hold of them.
Gloves are good.
Aren't they cute!