You can use now the Metadata Pointer Token Extension to add metada to tokens (not NFT's). This is way easier than using metaplex, and is a stardard since 2022, see this guide https://solana.com/developers/guides/token-extensions/metadata-pointer that coints a walk through on how to implement it. Here is a token with metadata created through this method https://solana.fm/address/5RDgetphrERHEwJMrkoKUqapzPXf4HMzcYwHbr3XtZ7C/transactions?cluster=devnet-solana