transactions – Someone said that they would send me bitcoin, they even sent me an exe file, called bitcoin.exe, which does not work

It looks like a scam, or at least an attempt to compromise your computer with malware.

Send to someone a bitcoin transaction DO NOT involve sending to someone an executable file. This involves using the bitcoin network to send a bitcoin transaction that moves a certain amount of bitcoin to addresses belonging to the participants in the transaction.

You can generate receiving addresses or send your own transactions using the Bitcoin wallet software. You only need to download this software after learning to use it and have found a reputable place to download it. In almost all cases, you should not download and run an .exe file sent by an unknown person.. If you have already done so, consider that your computer is compromised and never use it as a bitcoin wallet. If not, you will need to find a blank device for this purpose.

For more information on how to get started with Bitcoin, see: I'm new to Bitcoin, how can I get started?