As Arnav Bhaiya said, follow the article by DigitalOcean for installation of mongodb, but my query is within that article there are complex procedure within(which are given in pre-requisites for installation -> configuring server -> ssh commands ), which i am not able to configure on my machine (I am using ubuntu 18.04). I have tried it twice or thrice but nothing came out of it. Pease help me in the same.
MongoDB Installation(NodeJS)
You can follow other guide to install mongoDB in linux machine, like this one here
https://docs.mongodb.com/manual/administration/install-on-linux/
I have used this too and also digital ocean article that arnav bhaiya instructed.But on starting mongoDB service, I am getting this error everytime:
Failed to start mongod.service: Unit mongod.service not found.
What can be the reason , i have referred stackoverflow answers also but still issues is not resolved.
I recommend you to completely remove mongodb from your machine, and reinstall it using above link.
If the problem continues, attach some screenshot of the error or any relevant information helpful to understand the error.