Remove hair soap residue and other culprits.
Clean sink bottle trap.
To clear the clog you will need to clean your sink trap.
Inside with a bottle brush outside with a soft cloth and mild detergent.
Attach it firmly to the basin again and turn on the tap.
For mild clogs use a plunger or a baking soda solution to clean your sink trap and remove the clog.
Return the bottle trap.
Hair soap residue grease food and oil are all known to clog sink traps and drain pipes.
That dip down and back up is basically the same waste water travel pattern in use inside the bottle trap except the true p trap does so with a full length of pipe.
Screw the trap together again not forgetting any seals.
If you look at a sink and its plumbing from the side you may see that it extends straight from the wall and then dips down and curves back up much like the letter p this is called a p trap.
Use a bottle brush or other cleaning tool to remove any debris found in the trap.
Undo all nuts in the bath tub or wash basin and dismantle the trap into its individual parts.
For more stubborn clogs you may need to remove your sink trap to clean it properly.
You can also gently clean the tailpiece coming from the sink and slightly into the pipe in the wall to remove any gunk that may be present.
Remove the contents that are causing your kitchen sink bottle trap to block.