Sage has an Aatrix webinar this Wednesday 12/1/21 to review configuration and setup. You will note that this is for Sage 300. My hope is that this content will be relevant to Sage 100 as well since they both use the same Aatrix ( 1099 and W2 ) processing. 

https://www.sage.com/en-us/cp/isvwebcastsdec2021/