2 mkv files to one

[ratboys]

can somebody please tell me what program i use to combine 2 mkv files to make one movie file
(this movie comes with 2 mkv files)
thanks for all your help

[Baldrick]

mkvtoolnix or avidemux.

[ratboys]

thanks

[Seantagon]

im using mkvmerge gui, and i cant seem to merge to mkv into 1. whats the best way todo this? Ive tryed adding and muxing and ive tryed appending. One time it said successful but when i opened the newly formed mkv it only showed the first video

[Baldrick]

does they have same setting like video and audio codecs , framerate, resolution,etc? tried avidemux(open first mkv, append the next, save as a new mkv)