I need help.

Hello

I have a simple question. I created a website to wordpress and I want to make paid access to a single page.
I downloaded your plugin membership PRO
The plugin has been installed successfully
But I can not create a new Subscription.
When the menu Subscription plan, I want to add a new Subscription, when you click Add
Writes that the Subscription is added. But I do not see it on the menu.

Thanks