Ahh you only should have 1
<body> tag across all templates.
Then to switch which template is being shown it is easiest to use a router.
Instead of having two
<body> elements, structure it like this:
Another Page Here
I would recommend reading up on Iron Router, or FlowRouter though.
Without them, you would need to use
Blaze.render('otherpage') to change templates, either via a button or something.
Router makes it easy because it uses the URL path to choose templates.