You can access blower motor relatively easy, you have to remove lower
passenger side footwell trim and then you can remove the blower motor (
fixed with few screws) ( well you should also clean ventilation canals if
there are leaves inside) a bit longer procedure...

Btw. I have also bought used Focus few weeks ago. Problem is that
ventilation constantly heats... Please could you be so kind if you can check
if after driving a car for a while ventilation canals gets really hot and
warm air blows especially from lower ventilation openings.

Plastic case on the right from accelerator pedal gets so hot after half an
hour driving that you almost can't put your fingers on it .... I have been
to official Ford dealer to check this but he was unable to resolve the
problem...

Anyone can help? Is all this normal for Ford Focus? Car is without AC.

You need to change it. Mine did the same. After removing it, I notice a
lot of rust on the turbine post, because water leaked inside the car
from the exterior vent which leads right to the fan motor....!!

I got one for 140$ at a Ford dealer. And i fixed the leak.

To replace it, take off the glove compartment (3 screws) under it.

Then you will see the fan motor (black and round). Disconnect power on
the right side.

Remove the material under the dash (3 screws again).

And finally, remove 3 screws under the fan motor.

That's it.  Let us know how it went.

cheers,