Hi @Samar rai,
Here’s a link to the [https://www.lg.com/ae/support/support-product/lg-32MN58HM-P|user manual] for a LG 32MN58HM-P.
Is this the full model number of your monitor?
If it is, scroll down the page to find the download link for the manual and when you have the manual go to p,12 ''Selecting an input source'' to view how to connect a USB HDD to the monitor.
It does specify ''(Depending on model)'' so if your particular model is not the one listed above it may not work