Hi taki and welcome - although it is possible to grow a rose from seed - I think to be honest - that its something best left to the breeders who are experts at using this method to create new rose varieties - for the simple reason that for the average gardener the results can be extremely disappointing - as apart from the fact that the seeds very rarely come true to the mother plant - they are notoriously hard to germinate and even once germinated the seedlings are difficult to keep alive - unless you have the ideal conditions and temperatures to keep them in.
Which is why if you want to propagate a rose - the best way of doing it - is to take stem cuttings and insert them into the ground and if done at the right time of year - they will soon reward you with the beginnings of a new rose bush - which is far more satisfying than that of waiting 3 - 4 years for a seed reared rose bush to reach the size of the ones that you see in the nurseries - only to find that it doesn't even resemble the mother plant - especially after all the effort involved of nurturing it to that stage.
In order not to be disappointed again - when buying seeds online I think its always best to only buy seeds from reputable seed suppliers - who are known to supply quality seeds