Before jumping into the Dapp code you need to setup an Ethereum wallet. There are bunch of wallet applications and types outher, but for this project we're going to use Metamask.
A wallet is an application that let's you interact with your Ethereum account. You're wallet is the one that works as a gate between the Dapp and your data, through it the applications can read your balance, send transactions, etc.
You can swap wallet providers at any time or manage multiple accounts in one application. This is because the wallet are non-custodial, meaning that they don't hold your assets, you do.
Just to set some concepts down:
There are different types of Wallets: