At long last, after several long minutes - perhaps hours - or grueling preprocessing, you are ready to specify your general linear model. The concept is straightforward enough: Specify when a certain condition happened, input how long that condition took to happen (zero duration in the case of an instantaneous event), and what kind of basis function you want to convolve with that condition. Basis functions is a topic all on its own (you'll find out more when you're older!), but for the time being, realize that the canonical hemodynamic response function will suffice for most of your cases; even though sometimes it is a laughably wrong assumption about the shape of your hemodynamic response. But hey, it's the best we've got.
More details on the ins and outs of model specification, along with an example of what might be going through your head as you do this, can be found in the following video.
More details on the ins and outs of model specification, along with an example of what might be going through your head as you do this, can be found in the following video.