Overloading the_content()

Hi! Although a newbie, I am trying to modify a theme! Please bear with me and my silly questions! ??

What I am trying to do? Simple: making the post preview look good ?? Unfortunately I am unable to do what I want. Currently, I am using the ‘devart’ theme, and adding the line the_content( $more_link_text , $strip_teaser, $more_file ); shows posts weirdly:

My brand new post – Jan 01, 1900
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus in mauris dolor. Suspendisse consequat lorem eu mauris hendrerit porta. Vivamus cursus, metus in faucibus fermentum.

Diam tellus suscipit augue, nec vestibulum orci mauris vel neque. Donec a velit lorem.

I’d like to avoid the snippet to go on a new line, and possibly changing the preview to the first paragraph, or to less than ~50 words.

Is there a way to do that?

Thanks and cheers!!