How to buy train tickets

Hi everyone.
I�fm planning my trip to Japan and I�fm not going to buy the JR pass; instead I�fm going to buy the tickets separately and the jr Kansai Hiroshima pass.
I don�ft really understand where to buy the tickets. For example:
- to go to Takayama from Kawaguchi I have to take a bus, then a train, change the train and then another bus. I understand that the buses I have to book them , te question is about the train. Can a buy the ticket directly to the last stop or should I buy a ticket to the last stop is the first train and then buy another to take de second train? And can I buy them on the internet?

- the second question is that I�fm going to go to Kanazawa to Osaka. With the Hiroshima pass this trip is only covered from Tsuruga to Osaka, but not from Kanazawa to Tsuruga. How can I do this?

Thanks you!!!

to go to Takayama from Kawaguchi I have to take a bus, then a train, change the train and then another bus.

It sounds like you mean Kawaguchiko (Lake Kawaguchi) rather than Kawaguchi, the city. Do you? The Matsumoto-Takayama bus indeed requires advance reservations (can be done in Matsumoto in case there are vacant seats). Most trains between Kawaguchiko and Otsuki do not require seat reservations. You can use an IC card, such as Suica or buy a paper ticket. The trains from Otsuki to Matsumoto are fully reserved, so you better make a seat reservation in advance.

nd can I buy them on the internet?

Yes, the Otsuki-Matsumoto train can be booked here:
https://www.eki-net.com/en/jreast-train-reservation/Top/Index

- the second question is that I�fm going to go to Kanazawa to Osaka. With the Hiroshima pass this trip is only covered from Tsuruga to Osaka, but not from Kanazawa to Tsuruga. How can I do this?

Just buy a regular ticket from Kanazawa to Tsuruga, assuming you were able to get your Kansai Hiroshima Pass by the time you depart Kanazawa.

Thank you so much for your answer.

So, what happens if I buy the ticket to go to otsuki at 9 am for example and to go to Matsumoto at 11 and then I don�ft get there until 12? Can I change that ticket or do I have to buy another one?

And then, the Hiroshima pass can I exchange it in Tokio for example? Or do I have to do it in some of the west station included on the pass?

So, what happens if I buy the ticket to go to otsuki at 9 am for example and to go to Matsumoto at 11 and then I don�ft get there until 12? Can I change that ticket or do I have to buy another one?

Seat reservations can be modified once before the travel time, if needed.

And then, the Hiroshima pass can I exchange it in Tokio for example? Or do I have to do it in some of the west station included on the pass?

If you buy it through JR West, then you can pick it up at selected ticket machines in Tokyo, but if you buy it through a 3rd party vendor, it seems impossible to pick it up in Tokyo. It is explained here:
https://www.westjr.co.jp/global/en/ticket/pass/kansai_hiroshima/#purch...

Thank you so so much!!!

If you buy it through JR West, then you can pick it up at selected ticket machines in Tokyo, but if you buy it through a 3rd party vendor, it seems impossible to pick it up in Tokyo. It is explained here:

I searched the website, but it seems to say Kansai Hiroshima Area pass can not be received in Tokyo. If the OP travels from Kanazawa the actual station will be

frog1954 is right. While regular tickets reserved via JR West can be picked up at ticket machines with the "5489" logo even outside western Japan, rail passes by JR West, including the Kansai Hiroshima Pass, cannot be picked up outside the JR West service area. The closest stations to Tokyo where you could pick them up are Maibara (alog the Tokaido Shinkansen) and Toyama (along the Hokuriku Shinkansen).

And then, the Hiroshima pass can I exchange it in Tokio for example?

Nowhere in Tokyo.

Buying JR West Kansai-Hiroshima Area Pass through the official website,
you can choose Tsuruga Station to receive the pass.
https://www.westjr.co.jp/global/en/ticket/receive/?railpass=3&online=1...

Otherwise, you have to reach Kansai Region before receiving this pass.

Anyway, neither Toyama nor Kanazawa is among the pick-up places.

The pickup stations differ among the specific passes. As for Kansai-Hiroshima Area pass, this is the result.

https://www.westjr.co.jp/global/en/ticket/receive/?railpass=3&online=1...

Maybe Tsuruga is the station where you come from Kanazawa. If you choose JR Kansai All area pass

https://www.westjr.co.jp/global/en/ticket/pass/all/

you can pick it up at Kanazawa.

https://www.westjr.co.jp/global/en/ticket/receive/?railpass=10&online=...