If this is your 1st try at using the drill in vegetation, drill a bit. Any part of the drill can get clogged with plant material. Some drills don't like tall stuff, some drills don't like piles of mowed stuff.
Assuming a regular brush hog. I prefer open non shrouded finish mowers. Sharpen those blades, bring the rpm up to proper pto speed, and be mindful of the speed.
You could just drill if you put spray nozzles on the back of the seed drill.
What drill do you have? what spacing, what seed boxes? Whas growing there now? What do you want to plant? What kind of soil do you have? how level, rock, stumps? Some drills just want to dive in loose soils. Some drills are more designed for prepared soils and have lighter openers and press wheels.
You may want to get there a weekend before and toy around with the drill. Rye is generous in seeding depth, other seeds are not. Some no till offerings work well because they need to be seeded very shallow. Mow a section, dont mow another section.