@dzperrault Welcome back to using SAP Concur and welcome to the community. Below are links to our training toolkit. I think you'll find what you are looking for in regards to training videos and guides. Keep in mind that our user interface has changed a couple of times probably since you last used SAP Concur. In fact, we are going through a transition right now with our User Interface. I don't which one your company is currently using, so I've provided links to resources for each UI.
Legacy User Interface: https://www.concurtraining.com/toolkit/en/expense/end-user
NextGen User Interface: https://www.concurtraining.com/toolkit/en/expense/end-user/ui02
You'll have to log into SAP Concur and then open a resource from each of these links to see which interface your company is using.
I hope these help. Good luck!