Metadata for each token can include an image, animation, attributes, scalar properties, boost properties, and more!
You need node.js (8.11.* or later) and npm installed. If you want to do a Heroku deployment, download and install the Heroku CLI and run
heroku login locally.
heroku git:clone -a your-metadata-api, and
cdinto your new directory.
https://your-metadata-api.herokuapp.com). This is the root URL for the tokens on your contract.
git push heroku master.
Here's a tutorial on setting up a mintable NFT contract. Alternatively, you can have your buyers mint the tokens for you (and pay the gas to do that) at purchase-time, using the OpenSea Crowdsale Tutorial.
Now that you a contract and a token URI for each of your tokens, there's a nice mint.js script that you can run locally to mint them on a testnet like Rinkeby and on mainnet Ethereum.
If you want more control over the minting process, call _setTokenURI on your NFT's contract using the URL pattern above, either directly if you exposed that method for the contract
owner, or by minting new tokens using mintWithTokenURI.
If you're signed into MetaMask as the owner of your contract, you can click the "SELL" button on any asset to sell it immediately on OpenSea, using Dutch (declining price), English (to the highest bidder), and fixed-price auctions.
If you have questions, contact the OpenSea team on Discord. We're very responsive!