What happens during a team, squad, and platoon live fire?

This is the exact situation where you need to let people know that you lack experience. You'll be firing live rounds and mistakes get people killed. A buddy of mine got shot in the face in a shoot house during a live fire. No one will respect you less for your inexperience, but you'll lose all your respect if you get someone killed. Set aside your ego and go talk to your squad leader and your team. You will need to practice dry runs with them before you set foot on the live fire range.

I'm not Infantry but my gut instinct is to tell you that you need to talk with your Troops and your higher NCOs to let them know you're a reclass and to get trained up FAST.

Ask your PSG - I bet he knows ways to help you. Particular focus should be on practical exercises and rehearsal.
Practical exerises are where you present a scenario to your soldiers and have them describe their positions, duties and actions on the objective.
Rehearsals are where you and your soldiers first do a table top rehearsal, then a tape house walkthrough and then a full rehearsal in either the live fire area or in a detailed mockup. The mockup also can be tape house but better if the mock-up is 3D.
Definitely ask for help to perpare yourself.
Watch out for the war-story singers - they will just side track you.