IKKe benytter appen-do not use app-as dear anna fra Sverige ocksa links/tells every day dozens of times: do it via other ways, the railways themselves.

It should be obvious that you need to use much moreas 1 train-and it will also depend on actual route.

Most will use TGV to Paris (many more from Marseille-reach that via local TER), then whatever -via BE or direct to DE (note that via BE its expensive Thalys-due to no spare parts many trains out of service=no seats), so better go direct TGV/ICE to germany (best is Frankfurt)-OVEr border TGV cost an awful lot extra and are hard to get seats on=small quota. IN DE all the fast&always delayed ICE are optional to RES-if wanted (but expect them to miss due to delay)-as seat only via bahn.com

Next hurdles: in summer all DIREct trains Hambg-Köpenhamn MUST be reserved-and are often full (by all those Swedes that follow Gretha´s advice)-so can do it-slower-with more changes-Flensburg-DSB till Kolling/Fredericia-then K. Same from K: more chance to use Öresundstaget till Malmö-then X2000, as direct fra K. OR overnite snalltaget-fra Berlin-stops Hamburg-seat 199SEK extra-not varje dag.

ALT check direct TGV in FR from Marseille to Strasbourg=not via Paris (just a few/day), other side of river/bridge is DE-or visit EU offices to while away.

Du behöver fundera på hur många stopp ni vill göra på vägen, om ni vill åka nattåg någon sträcka. Dessa är dock troligen redan fullbokade. Om ni inte kan åka nattåg behöver ni övernatta minst en gång, kanske 2 beroende på vilka tåg ni tar.

Under sommaren är det obligatorisk reservation på IC tågen mellan Tyskland och Danmark, men det går att åka med regionaltåg med fler byten utan reservation. 

Inom Tyskland är det bara obligatorisk reservation på nattåg men det kan vara klokt att reservera ändå för att vara säker på att få en sittplats när man åker under högsäsong.

TGV och andra snabbtåg i Frankrike har obligatorisk reservation men det går att åka obokat med regionaltåg. 

Läs gärna den allmänna informationen nedan från de erfarna resenärerna i gruppen.

The advice from the experienced travellers in the community is to use other ways to make reservations than the Interrail/Eurail website. You can look at the guide in the link:

https://community.eurail.com/train-connections-reservations-47/how-to-get-reservations-105

If you, after having looked at the guide, have questions about how to make specific reservation, please give your travel details (departure date, time and route) preferably in a new topic, and you will get advice. .

Thanks for the replies, i will have to sit down and look at this for a while to understand what your'e saying exactly since im new to all of this.

Since it said it would take 30 hours to get from nice to stockholm we planned to do it in one go. I guess this wont be possible then.

Honestly i feel totally lost and confused… Dont understand how there can be no information about having to book trains multiple months before traveling....

Just ask here when you have more questions and you will get good advice.

Most routes are possible to make without reservations, using regional trains, but it will take longer time. 30 hours from Nice to Stockholm is by high speed trains and night trains. In Germany the high speed trains don't have mandatory reservation. 

Thanks a lot! I will leave more replies once i have researched a bit more.