Find the white Connect Wallet button on the top right side. Anything you do you can do on Mainnet, or on Testnet. To switch between the networks, click the Near Mainnet button and choose what you need.
After clicking Connect Wallet, you will be re-directed to the Near Wallet. It's an in-browser wallet - no application or extension needed.
The Wallet will tell you that you are connecting it with limited access. Press connect.
Then, the following screen will appear where they ask you again if you want to connect and to give the permission to mintbase to use up to 0.25 in Network Fee allowances. This will never be used without telling you, and you can actually log in with less on your wallet.
Click Connect, again.
You made it! You are signed in. You will see your near.name appearing in the place where the connect wallet button used to be. Now let's dive into the User Settings and start creating! You can also see how much Near you have here :)