Static home page!

Hi!
I am not too sure if this is the correct place to insert this post. I am still new to wordpress, so bare with me.
My situation is this. I like to create a static home page but with no menu to show on the menu bar until the user login/register. To understand better what i mean have a look at these two sites.
I like this site : https://www.skincare-service.com
to look like this one: https://www.weightlost4teens.com
Someone from my webhost helped me with the weightlost4teens.com but that person has moved on and now I want to do the same for the rest of my sites.
The idea is when a visitor comes to my site he/she sees nothing but the home page(static) where he/she get to register first. Then he/she gets a validation email upon which he/she gets a lick to click upon and get sent to my site but this time sees the whole content including the main blog as https://www.weightlost4teens.com
I know for you guys this is a peace of cake but for me being new to wordpress its not easy.
So, i appreciate all your help and suggestion.
P.S someone told me that there is a plugin for this.