Cant figure out where the shutter release cable hooks up oncamera

Need more info. What is the camera not doing? Does the auto focus work? Are the batteries good. Are the shutter blades in place? Sometimes when loading film a person will push down to smooth film and the force will go through the film and pop the shutter blades out of position. Remove the lens and gently lift the mirror with your finger nail. The blades should lie flat.

I'm assuming you need the whole chamber door. I think it would be pretty hard to find just the door, so I would suggest buying another HTsi Plus just to get the part you need. I looked on Ebay and saw an "HTsi body for parts". It was $30(USD) including shipping, not too bad. If there was a source to purchase just the door, I'm sure it would cost $10-20; so buying another camera body might be a better choice. You could probably buy a decent used/working HTsi for around $60-75. So it is up to you to decide what your best course of action is. If it is the door that you need, they are removed very easily (no tools needed).

On the top of the camera (right next to the shutter button, there is a button labeled "P". When you push that button the camera will go back to the default settings: Automatic Focus/Exposure. So just use the "P" button.

If it was only when you used the flash, make sure the camera is set to 60 on the shutter for the flash. If this is happening all the time, then you need to send the camera off for repair.

Can you trip the shutter?
If the shutter does not release, usually the camera repair shops would replace the shutter release capacitors.

The shutter is already wound and the shutter is not releasing.
You may have bad shutter release capacitors if the batteries are good.

This sounds like a common problem with this product, I hear this one a lot and this also happened on my camera. One of the only solutions is to contact the company's customer support and tell them the issue.

remove the battery

Minolta Maxxum lenses fit certain Sony digital cameras. Check this site as it depends on the specific model.

https://feltmagnet.com/photography/Digital-SLR-Cameras-and-Those-Film-Era-Lenses

Set camera to B , open back door and release the shutter and keep it open while you inspect focal plain area. Is the shutter fully opened ? If you release again is the shutter opening completely and closing completely ? While the shutter is fully opened on B look through the shutter/ mirror box area is anything obstracting your view ? Seems like one of the shutter curtains is not opening properly and shutter will need servicing. Please note that it may not be economical to repair : $ 150-200 if the shutter block does not have to be replaced completely.