One last comment: When writing up requirements, be careful to not put implementation details as requirements. For example: let us say you are a IBM mainframe

One last comment: When writing up requirements, be careful to not put implementation details as requirements. For example: let us say you are a IBM mainframe / COBOL. Putting in IBM and or COBOL as a requirement would restrict the development that might choice a raspberry Pi running Slackware and Java. And of course the reverse is true, despite being unlikely. There are probably some good books / online classes on the topic, worth a weekends time.