Transactions in Google Sheet - Move value from, to

I'm trying to make a document to manage my finances on google sheet, actually, I would like to be able to track the transactions I make between my accounts. I made this sheet to be able to sum things up.

Actually, I would be able to tell the document i'm making a transaction from - to (in that case, from content 1 to content 3) and to add a new value. I don't know how to tell google sheet to "move" 25 from content 1 to content 3 or any other content.

Thanks for the precious help.