Flash loans are a feature designed for developers, due to the technical knowledge required to execute one. Flash Loans allow you to borrow any available amount of assets without putting up any collateral, as long as the liquidity is returned to the protocol within one block transaction. To do a Flash Loan, you will need to build a contract that requests a Flash Loan. The contract will then need to execute the instructed steps and pay back the loan + interest and fees all within the same transaction.
If you would like to know more the procedure on how to do a Flash Loan, check out the documentation. Aave developers are also available in the official discord channel to help with the process.
Yes, there are already tools allowing end users to benefit from Flash Loans, such as collateralswap or defisaver. You can find more use cases at: https://medium.com/aave/sneak-peek-at-flash-loans-f2b28a394d62
It is even possible to use Flash Loans without coding skills through user interfaces as the one provided by furucombo. Here are more details: https://medium.com/furucombo/create-flashloan-combo-on-furucombo-c7c3b23267f0