The timeline shows "f" instead of Seconds

• Your composition is 2 seconds and 23 frames long at 25 frames per second
• Your footage is all 59.94 fps and the frame size is 1920 X 1080 unless the Clip 1.mp4 in Layer 1 in the timeline is scaled to fit the composition
• Clip 1.mp4 is almost 4MB and it appears to be 1 second and 20 frames long
• You have a total of 37.4MB of footage in the comp - Clip 7.mp4 has no file size listed so I assume it is a corrupted file
• If 4MB lasts for 2 seconds and you have about 38MB of footage then you need a comp that is about 19 seconds long

If you want to change the composition settings go to the Composition/Composition Settings menu or press Ctrl/Cmnd + k.

To change the time display from Feet and frames converted to timecode then go to the File/Project Settings menu or use the keyboard shortcut Shift + Alt/Option + Ctrl/Cmnd + k keyboard shortcut and open Time Display panel and change the option to Timecode.

You should only be using 25 fps as the frame rate for the composition if you live in a PAL country that has 50Hz power. In all NTSC countries, with 60Hz power (US, Canada, Mexico, and most of the rest of the world) the comp frame rate should be 23.976 or 29.97 fps if you plan to watch your project on television or 24 or 30 fps if you only intend to watch your project on computers or mobile devices. 23.976 and 29.97 also works well on computers and mobile devices. You only want 59.94 or 60 fps if you want the folks that watch your project to be able to pause the video and interpret the motion between the frames more accurately or you want them to be able to run the footage in slow motion without seeing any blended frames.

Your comp settings don't match the frame rate of your footage and you don't know how to change the settings so I strongly suggest that you open the Learn workspace or go to the User Guide and spend a couple of hours figuring out how to set up a composition and add footage to your timeline.