On item page at the bottom ,how can I change the items from scroll format to listing format?

@Dan
Try:
#rel-block .products.nice-scroll {flex-scroll:scroll;}

Thanks for the reply, would like to know

1.where should I put this code, In responsive.php or style.php ?

2.Another thing I need to know, do I have to just locate a particular code and change it or I just have to insert that code in a new line?

3. Also when I insert it anywhere on response or style its flex- scroll is highlighed as red

@Dan
First try then ask. You can even try it in browser.
You put that into style.css and should work.
Minor adjustments may be needed.