There are multiple exchanges supporting Monero. Some are centralized, which usually have great liquidity and fast service, but requires you to provide personal information before starting the trade (KYC). Some are decentralized and don't require any identification, but usually have less volume and can be harder to use. There are also services that allow people to meet and perform a trade without third parties involved.
There are multiple ways to acquire Monero: You can mine it, you can exchange services or goods for it, or you can convert other cryptocurrencies and fiat money to XMR. If you choose the latter, the most convenient way to do it is to use an exchange.
To securely verify the funds have arrived at your wallet, you will need to setup a View Only wallet. This is where that view-key comes in. To create a view-onlywallet see the entry: [View Only Wallets]({{site.baseurl}}/resources/user-guides/view_only.html)
To verify the funds are *still in* your wallet and have not been spent you need to create a Cold Wallet with your mnemonic key (all your funds) on an airgapped computer with an up-to-date copy of the Monero Blockchain. When finished you will have to securely erase the wallet or connect it to the internet and it becomes a Hot Wallet.
Unzip and open the paper wallet generator (monero-wallet-generator.html) into a web browser on an air-gapped (@airgap) computer that hasn't been used before, or has had a clean installation of the operative system.
Whichever method you chose, be sure there's no copy of the Monero wallet left over on the device you used. You may need to securely delete the Monero wallet if you saved it to a disk, or make sure your printer does not save a copy in memory.
