Make Forum

There are many people's here already suggested a few options.

But this one is more powerful and modern.

Follow the steps to install the following :

and register with your email address and enter the subdomain of your forum.

Whoa! Your forum is ready!

Now, If you have a custom domain, you can add it by going to freeflarum.com/settings

and following the instructions.

Without custom domain your forum would look like forum.freeflarum.com

but if you have custom domain you will get it like forum.yourdomain.com

If you want to add it to your blogspot.com

subdomain, then just add a page and add the following code to your page :

<iframe src="YOUR-FORUM-DOMAIN" width="360" height="720"></iframe>

Replace the YOUR-FORUM-DOMAIN with the actual domain of your forum.

https://www.quora.com/How-do-I-add-a-forum-to-my-Blogspot-blog