I'm not a developer myself, but Nat Eliason's blog is quite good on this: https://www.nateliason.com/blog/learn-solidity

Consider this to build a web3 web app, you're effectively building a web2 web app that talks to a smart contract on the blockchain. ​ If you're familiar with Java and Python, work on gaining confidence building traditional web apps that connect with a common SQL database backend first. Likely, you'll need to learn Javascript/Typescript as well as a UI library such as React. ​ After that, look into web3.js or ethers.js in order to connect your web app to web3 wallet and a blockchain such as Ethereum. The easiest starting point would likely be ethers.js and adding web3 authentication to your web app. This is basically using signatures to verify that the wallet is owned by the user. Effectively, their wallet address becomes a username, and the ecrecover function, which validates the signature, becomes the equivalent of the password verification. ​ From there on out, the next step would be to learn Solidity to build your own smart contract. Given a smart contract to interact with, you can extend your web app to call a smart contract by issuing transactions. If you're starting out by joining an NFT project, this is likely going to be calling the mint function of a contract implementing the ERC-721 interface. ​

You can start with learning blockchain development with ben's course on nas academy.