The recent posts with topics doesn't look correct on your website. It should look like this:

https://wpforo.com/community/recent/

It seems you've set 0 or 1 this option:

If you want any changes on this page, please copy the recent.php file of wpForo theme and customize as you want. More info here:

https://wpforo.com/docs/root/forum-themes/theme-customization/

I come back for a question.

In recent topic page, when we click on a topic, we go on first page... Why we can't go on the last answer last page ? 

It's possible to put only the name of last answer member ? and not the name of creat topic member ? it's easily to know who is the last member answer.

Can we make a button, when we click on it, all forum is read ?
For the new members, they can't easily forum activity with it.

We've inserted all available links in a one recent topic item. So it has all option. The link to the last post is available too.

If you want to only see a recent post you can navigate to Dashboard  >Forums > Settings > Topics & posts admin page and set the Recent Posts page type to "page".

I see it, but the problem is it takes more space for less visibility.

We can't put the last post in the link topic start ? 

If I select recent post, the problem will be I have 20 answers for the same topic... 

I'm sorry but there is no way to change the logic. We'll create a poll and make a decision based on votes.