Noob Question – Buddypress Dynamic content on static page

You need to open up your custom child theme and add a loop to the index.php. Or if you want it in the sidebar then you add it to sidebar.php with a conditional check if you only want it to appear on the homepage. If you only want to show one post you add something like this.

<?php
  global $wp_query;
  $args = array(
    'cat' => #, //add the category id of the posts
    'posts_per_page' => 1, // set how many posts to show in the loop
);
$wp_query = new WP_Query( $args );
while ( $wp_query->have_posts() ) : $wp_query->the_post(); ?>
   //setup the contents of the loop
   <h2><?php the_title(); ?></h2>
   <p><?php the_excerpt(); ?></p>
<?php endwhile; ?>