The height is automaticly set due to content you place in it, always and every page.

You can set the height of these in for every viewport in step2 template structure, select header, content or footer and set height to 0.

Anita, as a supplement to what Andre stated, you could also use an entry page (although the only option appears to be a timeout and automatic redirection to the home page), or you could select the home page, click properties, select graphic and click the box "create page without template". This would leave the template in tact for all other pages.