There are a lot of ways to do that honestly. You can sweep them. You can knock them on the head. You can jab them in the stomach and then crack them across the head. (Assuming that no one is wearing protective gear, even if they are, they just need to be struck hard enough to be knocked back/unbalanced so they fall over.)
The problem you’re having is you may not know how one fights with a staff, what the patterns are, or even how it moves while in combat. The average staff length is for it to be around the same height as the wielder, if slightly shorter. How long they are is balanced to height, so this results in most being different lengths. While the staff is usually wood, they can also be made of metal (though the wielder may wish to take precautions due to strikes causing greater vibration) which are also often hollow. Wooden staffs, such as the quarter staff, where the user knows they may be facing armed or armored opponents were often plated with metal strips to defend the wood from bladed/cutting strikes and shod on both ends with a metal for greater damage.
The greatest force is present in both tips of the staff and the ends are what you use to strike/do damage with.
There are a lot of different styles and techniques that use a variety of approaches, so I’m just going to go with the very basic beginners one I know.
Basic staff attacks begin on an X pattern. The staff moves in front of the body. It goes high, low, low, high.
Strike high to the head, then low the the thigh, this allows you to switch ends, strike low again to the other thigh (which previously struck high), then high to the head. However, when this completes you’ll find yourself in the opposite side of the X. In order to get back to beginning position, you either reverse rotation (you struck high, so low, low, high) or the staff rotates over to strike the top of the head. Then, this creates an opening to thrust forward.
Here are some basic strikes with the bo staff.
What is most important for you to notice and keep in mind: when the bo comes across the body, it must strike with the opposite side come back. The strikes also come across the body, to the outer sides. This is very important for you as the writer, because with writing staff combat these two aspects are often neglected. That the strikes primarily come to the outside of the body, the usage of both ends of the staff, and that the staff must rotate in order to be in a position to strike high or low and from the left side to the right side.
The Kung Fu/Shaolin staff, for comparison.
The Renaissance quarter staff. If you’re leaning closer to European styles. More quarterstaff. Scholagladitoria on how to hold a quarterstaff. And while you didn’t ask for it: his video on quarterstaff versus sword part 1, 2, and 3.
One of the best book series I’ve run across that describes staff combat is Tamora Pierce’s Protector of the Small. Mainly because it involves a lot of details about training which are routinely skipped and you need to know. I’ll point out, however, Pierce has a preference for Japanese martial arts in these novels and they were written in a time which coincided with increased interest in and popularity of Japanese history/culture and before the internet made it easier to access information on revived European martial styles. (Basic assumptions that were/are common in the history community and at large about Medieval European hand to hand/martial arts in comparison to Japanese ones are at play here.) Essentially, “Japan is cool” is a theme running through the novel. So, take it with a grain of salt before importing the attitudes wholesale.
It should be noted that none of these videos will teach you how to actually fight with a staff. If you’re interested in learning martial arts, my personal recommendation will always be to seek out a qualified instructor in your area and sign up for classes. On this blog, we always use videos from instructors and other professionals as a means to helping you as a writer learn the theory and to help your visualization.