You will need an adaptation of the ‘mullet loop’.
You will need something like:
<?php if (have_posts()) : ?>
<?php $count = 0; ?>
<?php while (have_posts()) : the_post(); ?>
<?php $count++; ?>
<?php if ($count == 1) : ?>
// if this is the first post, process any code that is specified in this region
// process any code specified in this region before the content of the first post
<?php the_content(); ?> // display the full content of the first post only
// process any code specified in this region after the content of the first post
<?php elseif ($count < 4) : ?>
// if this is the second or third post, process any code that is specified in this region
// process any code specified in this region before the content of the second or third post
<?php the_excerpt(); ?> // display the excerpt of the second and third posts
// process any code specified in this region after the second and third posts
<?php else : ?>
// if this is fourth or more post, process any code specified in this region
// process any code specified in this region before the content of each post
<?php the_title(); ?> // display only the title for all other posts
// for all posts after the third, process this code below each post
<?php endif; ?>
// for each post, including the first, process any code included here
// any code output will be displayed below the content of every post
<?php endwhile; ?>
<?php endif; ?>