To use external subtitles you should have an srt (lower case extension) file in the same directory with the same name. Like movie.mkv and movie.srt as example. Also you should select a proper encoding of your subtitle file using App preferences.
To use MKV subtitles enable "MKV extended support" feature in App preferences. Only SRT and SSA tracks are supported. Yet experimental - sometimes does not detect subtitles at all.
To link several VOB-files (like VTS_00_1.VOB, VTS_00_2.VOB etc) click on the .IFO file (like VTS_00_0.IFO) (not supported on Logitech Revue).
If you have problems when connecting to SMB shares with authentication enabled, try to disable it on you server. There are issues about accepting login/password on some kinds of smb servers.
You can navigate fast in file explorer using quick search feature. Just start typing to filter files.
If you have no sound, your video file may contain unsupported soundtrack (like DTS).
0-9 - fast seeking to 0-90%
A (ALT, Yellow) - change audio track
S (Blue) - change subtitle track
O - change Revue optical output mode AC3(DolbyDigital)/PCM
P - set Revue video output mode to 50Hz (PAL)
N - set Revue video output mode to 60HZ (NTSC)
+/- - change subtitle size
K/M - move subtitles up/down over the screen
</> - change subtitle offset in msec
Z - zoom/crop video (not supported by Revue and Co-Star)
X (Red) - change aspect ratio (only for 2nd gen ARM Google TV)
E - enable/disable external audio track (media will restart)
R/T - change external audio track offset in msec