1，无经验。欧铁通票的官网上说可以用，在火车站窗口订票。详见后附原文。
2，再次提醒，欧铁通票在90%的情况下都是亏的。以你这程为例，在德铁官网上买，提前的话含订座是19.9欧。而用通票要用掉一天（平均40-50欧），外加4.5欧订座费。

https://www.eurail.com/en/deals/eurail-pass-benefits/benefits-germany

As a Eurail Pass holder you can travel for FREE on IC Bus connections passing through Germany. With this, you can travel to cities in 10 countries, as long as your Eurail Pass is valid in all the countries you travel through. A €4.50 reservation is required.

Which routes are covered?
Berlin Hauptbahnhof Europaplatz - Rostock/Hamburg - Copenhagen (Denmark)
Berlin Hauptbahnhof Europaplatz - Warsaw Airport (Poland) - Warsaw Zachodnia station (Poland)
Düsseldorf - Maaastricht (Netherlands) - Liège (Belgium)
Düsseldorf - Roermond (Netherlands) - Eindhoven (Netherlands) - Antwerp (Belgium) - Ghent (Belgium) - Lille (France)
Frankfurt Main - Frankfurt Hahn Airport - Trier - Luxembourg City (Luxembourg)
Leipzig - Prague (Czechia)
Mannheim - Frankfurt - Prague (Czechia)
Mannheim - Heidelberg - Nuremberg (ZOB) - Prague (Czechia)
Munich - Regensburg - Prague (Czechia)
Munich - Zürich (Switzerland)

How can I reserve a place on the bus?
Tickets and reservations are available at railway ticket windows in Germany. Due to seasonal route changes, it's worth checking the dates of your preferred route on the DB Bahn website before you travel.