Since MetaMask works by connecting your web-browser to an application running on the blockchain, MetaMask needs these permissions to form the connection and establish the flow of data between the blockchain and your web browser.
To maximize security, consider running MetaMask in a browser profile that only consists of MetaMask. This creates a separation between regular browsing activities and MetaMask activities.
Click on `Add Extension` and MetaMask will finish installing and open a new tab with a welcome screen. Congrats! You just installed MetaMask browser-extension