Using RAILGUN is simple, even for those new to DeFi and blockchains. You will need:
Network base tokens for the chain you wish to use (ETH for Ethereum & Arbitrum, MATIC for Polygon, and BNB for BNB Chain).
Assets held in a self-custodial EVM wallet (popular options include Frame, Rabby, and MetaMask)
After this, you will need to select a frontend from the list of independent providers at https://railgun.org/wallets, there is no single or official frontend for RAILGUN and all providers are built by independent community members and partners.
Once you've selected a frontend, you can generate a 0zk private address to which you can shield tokens.