Unzip the route/train files (if they are already compressed). After opening the openBVE program, you can directly use the browse function to search for files.

Select the route section (Railway\Route\__.csv) file.

Select the train section (Train\) file.

Its probably my site that are full of trains and youtube videos

No, definitely not. Instead, you should try using a converter to convert any Openbve files before imported into Hmmsim 2