Hi I'm from Hawaii,I'm going to Osaka 4/28 to 5/6 on Golden week. how do I buy train tickets to Tokyo?

Obviously neither of the first two people to respond to your question bothered to actually read your question. You don't want to buy them at the station. You obviously realize that the trains will be crowded and want to BUY YOUR TICKET NOW, AS IN ADVANCE. The way that I would do it won't work for you because I would jump on my bike, ride 5 minutes to the nearest JR station, throw down my credit card, and buy the ticket. But I did find this site.... https://www.yoyaku.eki-net.com/PC/Personal/Common/ReserveTop/ReserveTop.aspx You can translate the page. I did so. It is not completely intuitively obvious, but you may be able to figure it out. I gave up after a couple of minutes. But it is a start. You should also consider a JR Pass. You're going to spend about 26,000 to 28,000 yen for round trip Osaka/Tokyo. You can get a 7 day pass for 28,300 yen. http://www.japanrailpass.net/eng/en003.html This may make it harder though to reserve a seat ahead of time. Lastly, as a note, I have ridden the shinkansen on two occasions from Tokyo to Osaka without a reserve seat during rush seasons. No reserved seat. And didn't get one in the non-reserved cars. Stood up all the way. Point is, it isn't pleasant, but it will get you where you are going.

You can buy them at the train station.

Obviously neither of the first two people to respond to your question bothered to actually read your question. You don't want to buy them at the station. You obviously realize that the trains will be crowded and want to BUY YOUR TICKET NOW, AS IN ADVANCE. The way that I would do it won't work for you because I would jump on my bike, ride 5 minutes to the nearest JR station, throw down my credit card, and buy the ticket. But I did find this site.... https://www.yoyaku.eki-net.com/PC/Personal/Common/ReserveTop/ReserveTop.aspx You can translate the page. I did so. It is not completely intuitively obvious, but you may be able to figure it out. I gave up after a couple of minutes. But it is a start. You should also consider a JR Pass. You're going to spend about 26,000 to 28,000 yen for round trip Osaka/Tokyo. You can get a 7 day pass for 28,300 yen. http://www.japanrailpass.net/eng/en003.html This may make it harder though to reserve a seat ahead of time. Lastly, as a note, I have ridden the shinkansen on two occasions from Tokyo to Osaka without a reserve seat during rush seasons. No reserved seat. And didn't get one in the non-reserved cars. Stood up all the way. Point is, it isn't pleasant, but it will get you where you are going.

You can buy them at the train station.

Golden Week is one of the hardest times to get Shinkansen tickets in Japan. And you can't reserve it from another country. The only option is to get JR Pass and take Shinkansen no matter you have to stand as 3day says.

Osaka → Tokyo You can buy the ticket at the station (Shin-Osaka) in that season. The opposite way is harder to get it. It costs about 13,000 yen.

Osaka → Tokyo You can buy the ticket at the station (Shin-Osaka) in that season. The opposite way is harder to get it. It costs about 13,000 yen.