Dropdown menu not showing when using bootsrtap

HTML-CSS
#1

https://www.w3schools.com/howto/howto_css_mega_menu.asp

open this page use
link href=“css/bootstrap.min.css” rel=“stylesheet”>

i want to uss this above bootstrap.css as i am working with bootstrap grid section my content.

#2

the above code not showing dropdown button hover with bootstrap

#3

in bootstrap there is no any such way to show menu dropdown on hover, but you may only using mannual(pure) css or javascript.
for better solution,you have to post your code here

#4