I integrated the Coaches Console website on my external website and there is a scroll bar present in the integration page. Why is that?

A vertical scroll bar is most probably due to the fact that the height of your external website template is shorter than the height of the Console website template. Correspondingly, a horizontal scroll bar in the Console integration page is due to a width of your external website template that is smaller than the width of the Console website template. If you want to eliminate the scroll bar, the solution would be to enlarge the dimensions of your external website template (page) accordingly from the HTML code.