You can highlight any topic type, from any category, as 'recommended' content. This is useful for content that answers a lot of questions, has a lot of views and helps a lot of your users.
By default recommended topics lists are shown in 2 columns. In this post you will learn how to list the topics in 3 columns.
Learn how to add Custom CSS in this article: How To Add Custom CSS
Test first: Consider using your staging environment first to test and try your changes before applying them to your production community
3 columns of recommended topics

Set up your topics in Homepage Customization Mode
Then apply the following Custom CSS
/* recommendation 3 columns */
.custom-featured-topic-list .box__pad {
padding-right: 0;
}
@media (min-width: 1025px) {
.custom-featured-topic-list .topic-curation__item {
width: 33.3%;
}
}