flash photo with GSN

Hi ,

I want to take some indoor shots with a Yashica GSN. I am however not
certain how to do it.
As i understand I have to put the flash iso setting let's say at 100.
Then the distance to the subject gives me the aperture setting, let's
say 8. The camera is a aperture proiority so it shall decide the
shutter itself. Is it really sure that the camera does it right. I
understand that if I put the setting of the camera on flash it may do
it but the Yashica Guy page says put the setting on Auto for
electronical flashes. Does that mean that putting a flash on the hot
shoe or connecting a flash wire on camera make the camera understood
that a flash is on camera? another question is that is it a good
choice to use 100 iso films? And finally am I more comfortable to use
a SLR or the Yashica will do the job as well.

Best regards,

Mojtaba

the email address above is fake.