I use a 70D , I’m not sure that I would help much being so new. I populated all the camera settings basically by google searching the info from photography testing websites. There is a lot of information out there.
One thing in particular I’ve run across is that for the majority of Canon camera’s most of the websites recommend ISO 1600. I forgot the site but one even has graphs of the data and ratio between the gain and the noise at different ISO settings.
What’s most interesting though is that at least with the 70D the graph drops off significantly after ISO 800 yet 1600 is still the number recommended by most.
I have done some limited testing in this area, but anecdotally I can say that I feel like my data is better when I’m shooting long exposures at low ISO (5 to 10 min subs at ISO 400 or 800). This is at a green zone darksite. If I’m in my driveway using a LP filter (Baader semi-apo filter) then I’m always at low ISO
Now the flip side is that I’ve managed some really good images (imho) at ISO 1600 also doing 5min subs.
I guess the short answer is I need way more “equipment” time.