Yes-use other means, as we tell about each&every newbee here a few dozen times daily. This also saves you the 2€ extra fee. seewulf has made an extensive overview of countries and how to do it.

And IF you want more detailed advice-start with some thinking: then also provide complete details. The most common error for those from over the ocean is being waaaaaaaaaay too early.

You can look at this guide where various ways of making reservations are described.

Most reservation are better made elsewhere than the Interrail/Eurail website. 

It sometimes helps to book the train separately. But most reservations are indeed better booked elsewhere.