Visual training materials to understand IT / firewall & data transfer security.

At work I often have to liaise with the security and network team to get firewall permissions approved and there are always delays as they have to liaise with the suppliers about their connection methods, ports, standards etc.  I would like to understand this more so I can ask suppliers about the flow of data at an earlier point in time to reduce delays.

I have a reasonable IT background but when it comes to all of the security based terminology I get confused.  I am aware that different standards such as TLS change over time but not what it means or it's impact / implementation.

For simple example, how is port 123 more secure than port 456 and how does the port number stop unauthorised access?  In basic terms I understand that when using FTP the data is transferred in plain text but using SFTP the data is encrypted and assume other standards work in different ways at different levels of encryption.

Can anyone recommend maybe some good online interactive demos on these topics or even online courses to help me understand the concept of security.  I am more of a visual learner but in this case don;t have access at that level.