Install the MetaMask wallet
You may install a wallet,following the instructions on the site
Then add the Polygon Mainnet network in MetaMask
The easiest way to do this is to click on the «Connect Wallet» button via a service and then «Add to MetaMask»
Click on the «Buy NFT» button
There will be presented NFT-cats collections which you can purchase
Choose the desired collection and click «Buy NFT»
Each collection can be selected separately, clicking the «Buy NFT» button below it
Connect the MetaMask wallet and choose the amount of NFT you want to get
Maximum you may buy 5 NFT per one time. The formation of NFT occurs by accident
Click on the «BUY» button
Perform a transaction
Purchased NFT are on Opensea.io in the section «My Collections»
On your Opensea.io account you may review your brand-new NFT