For me, this is the most daunting part of the compliance process. Definitely outside my comfort zone.
Still work to do here
I have to confess that I am unlikely to have this completed for the 25th deadline. I am in conversation with IT support contractors I use and everyone seems to have a different appreciation of what is required.
What is the TOSM
The TOSM is a comprehensive check list of the data and organisational issues you need to deal with in order to be compliant with the GDPR.
Read the support documentation
Again, you will find supporting documentation in the support portal. Where necessary you will need to consult with the staff or outside contractors who look after your IT and other related matters.