Before you install NanoWallet, make sure you are using a computer which is clean (Antivirus-/Antimalware-Scans) and always use a strong, unique password (read more about it here).
Download the NanoWallet from nem.io. Extract the zip file and double-click "start.html"
Please do not use Microsoft Edge browser, it can result in the loss of your wallet. We recommend Google Chrome or Firefox.