How to handle Software/Firmware to be MDR compliant?

I just listened to your webinar about EU MDR. It was quite rewarding as there were few surprices but still some good information. I have a more specific question regarding software. Background: We have a unit that cuts out a form in styrofoam which is then filled with a low melting point alloy. This hardend form is the put between the patient and the source of radiation to limit the radiation to certain places. The unit itself has the technical documentation made. However there are two aspects which I am uncertain how to handle: 1) Software. There is a computer software that receives input from user (from xray etc) and then converts the desired shape to be cut. 2) Firmware. The unit itself has a firmware implmented that receives the data from above software and performs the actual control of the unit. My question is: How are these two to be handled in the technical documentation? Most of the standard sections do not apply to software (Biocompatibility to name one). So.. how to handle Software / Firmware to be MDR compliant .