If you’re genuinely asking, advance scouting is basically working ahead and outside of the immediate opponent to streamline and simplify. If you’re playing Detroit this week, it’s breaking down and charting what Arizona has been doing so their on-field staff isn’t starting from ground zero on Monday morning of that week. And then continuing to work ahead and/or going back beyond the most 4 recent games which is what most tendencies are based on. Also some around the trends on how things are being exploited so you have counters.
In his case as an offensive guy who was working with the defense, it’s also putting together the scout offense and being able to install it from that point of view. For people worried that he wasn’t involved directly in the GB offense, one benefit is that he probably gathered some elements from various offenses that he might want to add as tweaks to his existing views.
EDIT: This was all about Lester and his role in GB, not Budmayr.