How to tell the manager?

How to tell the manager this?

So the manager just put me on the schedule to train with another department. Some people at my department are trained to preform both tasks. So the manager thought its a good idea to have new hires to do the same. She didn’t talk to me about she just put me there. The evening employees kept acting pissed with me that I am training with their jobs description. I tried to be polite and nice and told them that the manager thought I could help out in the future. They kept acting angry and passive aggressive they said we did not receive an email from your manager. Tomorrow should be my last day but I feel pissed. What should tell the manager. I feel like they need to know because its a miscommunication that I paid for it. Plus one of the devices was missing so 50% of my training was not done. The manager did not bother to find it.