Add mass airflow volts to your channel list. There is a gear with a plus sign, and then you can use the search box to search for 'mass' and see if mass airflow volts is available.
Right click your graph section, and select graph lay out. Open the file im attaching, and it should populate the graph with what you can paste special % half into your airflow vs voltage table.
You will also want to disable LTFT under fuel> oxygen sensors. so that the only correction is from the short term fuel trims. You can enable them again once you have done a few logs with very small STFT's.
I would suggest start off in part, rev the engine to 1500RPM and hold it for 20 seconds or so, then rev it to 2000 and hold for 20 seconds, then 2500, then 3000, then 3500. The RPMs dont need to be exact, just rev it up a little and hold it as steady as possible.
This should get you enough data to get the lower part of your airflow vs voltage close enough to drive with no issues. When you do go for a drive you will want to do the same thing, put it in high gear and give it 20% throttle and hold it there a few seconds, then 30%, then 40%, then 50 %, etc. This should get you dialed in further up in the voltage. Then you can go out and choose a gear like 3rd or 4th and do WOT pulls from 2500-4500, then 2500-5000, then 2500-5500, etc.
Once you get done with all that the curve should be really well dialed in, and you can start on spark.
STFT.Table.xml