I'm taking the train by myself for the first time. Help!?

I'm 15 and taking the train from Bristol to devon which takes about 2 hours. I have to do it by myself with my luggage too. I'm only going for 4 days so I won't have a lot but should I put my luggage under my seat or somewhere else? And also I have a seat reserved so if it's busy I can sit down. But

I'm 15 and taking the train from Bristol to devon which takes about 2 hours. I have to do it by myself with my luggage too. I'm only going for 4 days so I won't have a lot but should I put my luggage under my seat or somewhere else? And also I have a seat reserved so if it's busy I can sit down. But just terrified of doing it there and back by myself. What should I do?

Other answer:

Abi:
Just remember that literally millions of people travel by train in the UK every day – and not one of them has ever done a training course on how to travel by train!

Seriously, as I never tire of saying here, the railways find that having loads of passengers wandering around like lost sheep, not knowing where they are going or what to do next is very inconvenient. They clutter the place up and get in the way. Therefore they provide lots of signs, maps, information displays, announcements and staff to ask. You will be perfectly OK if you get to the station in good time, look at the display boards and – above all – ask the train conductor or other staff if you have any queries.

On long-distance trains there are racks for passengers' luggage are at one or both ends of every carriage, whilst smaller items will fit in the overhead luggage rack. If you are at all concerned at leaving your case/bag in the end luggage racks, buy a small padlock and chain – a bicycle one will do – and chain the luggage to the rack. Just don't forget to unlock it BEFORE you arrive at your destination!

Relax and have an enjoyable trip!

TEE S:
You'll be cool! But don't put your luggage on the seat – it's for people! There should be either a rack over head or a little rack at the end of the carriage. You'll love it trust me. If you have reserved seat and someone is sat there, don't take any nonsense from them. Demand they move. If they won't call the guard/manger.
Christopher:
There is no room under seats – there is an overhead rack for small items. If you have a large case you may need to put it in the racks at the end of the coach.
Tom B:
relax… act like you own the place…. study others where to place your luggage…