The Day view displays a single day of the calendar.
The Day view is added to the basic scheduler's markup by default. That's why you don't need to provide any extra code for adding the view to the scheduler.
//just usual initialization. The Day view will be added by default scheduler.init('scheduler_here',new Date(2019,0,10),"week"); ... scheduler.load("/data/events");
Related sample: Basic initialization
To remove the Day view tab from the scheduler, remove the related div from the scheduler's markup:
//remove this div to remove the Day tab <div class="dhx_cal_tab" name="day_tab" style="right:204px;"></div>