Now since we have discussed upto deploying smart contract on Ethereum blockchain we shall now see how we can connect with the smart contract from our application.
Once you have chosen your proper web3 provider its now time to get the instance of smart contract you have deployed. You can get the instance with web3 api and interact with smart contract also and then things are very easy.
For front-end/client side DApp building
(Truffle/hardhat/Remix) + (Metamask) + (Web3.py) + (Flask/Django)
For back-end/server side DApp building
(Truffle/hardhat/Remix) + (Infura/Alchemy + TruffleHDWalletProvider) + (Web3) + (NodeJs)
You can follow these topics for further reading :
You can take the complete course on building DApp on ethereum