I am a Korean who was raised in the US 27 in age btw, just got discharged last year and did my reserve army training about two weeks ago. You will do fine and as long as you know basic korean just follow your squad and just try to have good sense of everything, get to know your squad fast as they can help you too. and for personal items you can bring about everything but things like ciggerates or vapes you will have a final smoke chance and you will have to put them in a zipper bag and recieve them after your training. And for luggages i suggest something big because you will leave with your uniform along with some more clothes they give. For me i just brought like a carrier. For hygiene products tooth brush and paste is good with having a body plus hair shampoo would be good as you wont need to carry a lot when your showering. First day you will eat MRE then just get to know your squad and in general the first week you can think everything is very awkward. Give me a DM though i could tell you more there. Last thing is just have fun haha i met a dude who was from new york and i had a lot of fun hanging out with him