I think you have a great idea about where to go next. I can see how your previous experience fits in with your interest in MSW. Did you deal with any face to face walk ins? Did you handle any calls that went directly to you from a main number? If any of those were true, you dealt with Customer Relations/Public Relations. You don't need to puff it up, but you were the face of the company. How you interacted with the public in person or over the phone had a direct impact on company revenue. If you have a bad interaction with someone, I guarantee they'll tell someone and maybe next year their company wouldn't renew a contract with your company. The main thing you can show is that you didn't just sit there and answer the phones. You had responsibility and made decisions (who to let in, how to represent the company, etc). Those fit in well with your interest in HR.
- You trained 3 employees. That might seem very simple, but that's not something that everyone can do. Some people don't even have the patience to spend time with a trainee like that. Did your responsibilities change after you trained those people? If so, mention that.
- Even handing out badges is important. That's basic company security. Letting the wrong person into the company could result in theft of property or company information. The confidential information is equally important, even better if you can expand on what that was.
- As far as "difficult decision". Did you ever have any visitors that didn't want to wear a badge, didn't want to follow procedures, etc? Use that. Was there any time you had access to confidential info that you shouldn't have, and you had to decide what to do?
You don't need to exaggerate any of these, just use your real example. You can easily show that you worked in reception because you liked working with people. (Not everyone does!!) That is a great way to talk about why you want to work in HR (and later MSW/Career Counseling).
Good luck!