how to put author and date under post title

hello,

i have this code which creates a date stamp and author :

<small><?php the_time('F jS, Y') ?> by <?php the_author() ?> </small>

however where ive placed it, (##index.php and single.php) has ended up showing above every post

seen here: https://www.citizenstars.com

how can i place this code within the post and under the post title, as my theme did not come with time stamp, author etc. any help?

further, if anyone can even point me to how i can customize this, rather than just simple text, (sorry thats 2 questions)

##ive had to place this code in both of these .php pages, so that it appears on front page and actual post page,