aman wrote

No problem, we all have been newbies at some point.

I did this, there are other ways too.

Draw a horizontal line, then select it by clicking. It should change to short lines. Then I select from the top menu Tools > Modify or from the left panel the + icon, it is the same, Modify. I select Move/Copy, Reference point is asked, I select either end of the line (select end points from the bottom snap options). Then I can move the cursor above or under the selected line, I click where I want to copy the line, confirmation window is opened, where asked if you want to keep or delete the original, or do multiple copies.  I have LibreCAD 2.2.

Ask more if you need.