What is wrong when the milage indicator starts to flash on my KA car

The sounder needs replacing.

https://www.google.com/search?q=2010+ford+ka+indicator+sounder+not+working

and

https://www.google.com/search?q=2010+ford+ka+indicator+sounder+location

..

possible intake manifold gasket.

Alternator failed, Chek voltage at battery should be 14. 7 volts.

does the engine crank over.
if it does, do you have both keys to the car,1 red 1 black
the red one is the main key and is the master key if this dosent start the car then i would surgest the car imobeliser/alarm system fuse

Could be various things. Can be the indicator stalk - the actual lever that you push down / pull up inside the car. Take cowling off check wire connector.
(Is it both ways it does this?)
OR, simply the bulb and/or the bulb holder? They get corroded. Whip the bulb out and see the bottom metal part of it. Is it manky / corroded. Is the seat where the bulb sits wet and have white residue?
It does sound like the switch is simply jumping out from the lever.
Ya know if you indicate, it clicks itself off as you straighten up your wheels? Try looking see if the switch between steering wheel and stalk is broken or conflicting / inhibited by foreign bodies? I'm more the under bonnet amateur stuff really, sorry.

you have two problems both bad your oil pump is going out, and your trans is about to go out also. both very expensive if you can trade or sell car soon.

sounds like the relay is shot, try the hazards see if they work and get back to me?

Hazard warning lights and horn on a 2006 Ford KA don't work but indicators do

Some times there is chime to indicate cold temperature and the temp will flash on the tach. When you start up there is a chime when you are due for service. check the speedometer at the milage reading when you start your car. it will say under it oil service or inspection that is the mileage left till the service should be performed. Let me know if this helps.