For blind and visually impaired Twitch streamers, using the schedule extension is currently not possible without sight. Selecting days of the week are okay, but selecting the hours and naming events is the inaccessible part.
An alternative method, if the current method cannot be made accessible, is to simply be able to type your times in, followed by the event name. Example:
10:30 AM - 2:30 PM - Insert event name here.