It's always nice to get a new college to yjoin the group :>)
It's quite difficult when you never programmed a PLC to give you an anwser to your question. It's to general.
First of all you should know that every plc brand has his own programming software. Before messing around with that part try to fully understand ladder programming and the use of it.
Then start with one brand to get the hang of it. When you have a question I'm more than willing to try to anwser you question.
JV