Hi Nicolás,
If you are hosting the site on business catalyst then you integrate the forum's module in your muse site, just like how blogs are integrated. I don't have an tutorial video on forums integration in Muse, but the process outlined in the one below, which is for blogs, would be very similar to integrating the forums as well.
Muse Jam Sessions_50_EmbeddingBlogs
- Abhishek Maurya