error in terminal

I installed the package using npm. I obtained an API token from https://nft.storage and use it in place of API_TOKEN. I named my script index.mjs. When i Run the script: node index.mjs, I get an Error: Cannot find module ‘/Users/ronlawrence/index.mjs’

Also, what does “use npm init to create a new package.json” mean? Once I figure those two parts out i think I will be ok. Not sure what I am doing wrong