Private Key Generation

Hello,

Where can I find documentation for how a private key is generated + what it involves?

I tried looking at: https://github.com/input-output-hk/cardano-sl/blob/master/wallet/src/Pos/Wallet/Aeson/WalletBackup.hs

Example:

"In Bitcoin, a private key is a 256-bit number, which can be represented one of several ways. Here is a private key in hexadecimal - 256 bits in hexadecimal is 32 bytes, or 64 characters in the range 0-9 or A-F. " from https://en.bitcoin.it/wiki/Private_key

I want to generate a private key by coin flipping so I need to understand how this works.