How to make register page as homepage?

Dear friends,

Good Day!

I am using elgg 1.8.8 version with cool theme.

Now if I visit my site as guest it shows only river activities and login area. 

but when I visit my site as guest then does not show river activites. and shows a nice sign up page.

So my question is how i can make default this page >> page  instead of this >>> for guests only?

I want my guests if they visit my URL then they see only content but the URL will remain the same as without /register 

I hope you understand what I want,

Look forward to your kind reply / help.

Many thanks in advance