problems of opening a raw project

hello forum friends. good thing is that you record a session of about an hour to save the raw files but when I open that file only opens a few seconds of the file. and in the same folder there as about 300 audio files. and read in pages and says I have to merge files to open the entire project, but nose how. I hope your help please and thank you … use ubuntu 12.04

Please see here for how to manage Audacity projects: