Depending on how you installed the software, you can log in as root or as a user if you used a package.
You will now see 4 separate windows appear. The top 2 windows from left to right are the Viewer which is most useful for previewing clips and media and the Compositor which displays the current working frame at the timeline position. The bottom 2 windows are the CINELERRA-GG Program, also called the timeline, which is where the real work gets done and the Resources window showing a selection of media or effects.
Any of these windows can be resized to better suit your needs. Note that if your system’s native language is not English, some of the words you see on the screen will be correctly translated for you, others will be in english, and some will have not very good translations.
It is important to know that CINELERRA-GG does not directly change your media. It writes all changes to what is called the EDL, Edit Decision List. This way you original media remains completely intact.
The CINELERRA-GG Community, 2021