This is not a easy answer
As ON-ramping with FIAT is country specific now
nobody will document all local solutions here for privacy reasons. 
https://bitcoin-intro.com/ - looks fair
Key is to use basic mainnet wallet only as first time self-custody user - Bluewallet on android + IOS best to start. GetAbly LN-Wallet and Sideswap LQ-Wallet. Green-Wallet with JADE next to learn