@Nirmal Joshwin
goodluck then, I hope you get a GT 1030 GDDR5 for a good price.
is this your first time installing a GPU?
here are the steps if it's your first time to install one.
first: download this driver, it's the official Nvidia website. So it's the safest place to get gpu driver. After you've downloaded it, just leave it at the desktop. I assume you're using windows 10?
Download the <dd~LanguageName> <dd~Name> for <dd~OSName> systems. Released <dd~ReleaseDateTime>
www.nvidia.com
second: turn off the power of the pc. Insert the gpu into the pcie slot. Screw it to the side of the case.
three: attach dvi cable or hdmi cable from your monitor into the gpu. Btw, hdmi is better imo.
four: turn on pc. The desktop will be on very low resolution, but don't worry. Now double click, the gpu driver that is on the desktop. Choose "Express install" personally, I also let it install Geforce Experience, but you can choose not to have it.
five: have fun with games.