Salutation register button or sign up form

Hi,

We have bought a Buddy press theme called Salutation. This theme has created a register button with some text in it that can be removed or kept.
Anyhow, on the demo site, when you click on the sign up button it goes to a sign up form. On the theme we bought, it doesn’t. I assume I have to make the form (wondering why it didn’t come with the theme!). This form lets people to sign up to participate in forums.
I am not sure how to make a form, and how it adds people as members.

Our url is:https://euromura.com/
I would appreciate if someone can help me with this.

Thanks a lot ??