The hotel's nearest train station is called “Bad Aibling Kurpark”. It is served regularly (every 30 to 60 minutes) by regional trains (Meridian) from Munich (München Hbf or München Ost) and Rosenheim. The trip takes roughly 70 minutes. Munich main station can be reached easily with long distance trains from many European countries. The detailed time table is available on the website of German Railways: https://www.bahn.com/en/view/index.shtml
The nearest airport is Munich. From there trains (S-Bahn) are leaving every 10-20 minutes towards Munich. Two different lines are available. You can either take the S1 to Munich main station (München Hbf) or the S8 to Munich East (München Ost). From München Hbf/Ost you can take the Meridian as described above. The trip takes between 90 to 120 minutes.