First off you need an intervalometer (if your camera doesn’t have one built in) and a tripod.
The intervalometer instructs your camera to take a photo every x seconds. For a 10 second clip, you need 250 images – so if you take a shot every 10 secs you’ll need about 42 mins of shots.
I set the camera to Medium JPEG as this creates 3088×2056 images. This allows you to crop to create a 2880×1620 images which are easily scaled to 1920×1080.
The images need to have exactly the same settings for each image or a significant flicker will occur. So the ISO, shutter speed and aperture need to be fixed at manual. Also, a DSLR when autofocussing will open the aperture, focus and close it again – so manual focus is needed. When framing, remember you’ll lose about 5% of the image on each edge.
Once you have the images, check for camera-shake. Use the FFmpeg deshake filter to fix it.
ffmpeg -r 25 -pattern_type glob -i '*.JPG' -vf deshake=-1:-1:-1:-1:48:48:0:4:64:0,crop=2880:1620:100:100,scale=1920:1080 -vcodec libx264 -b 10M -bt 100k -pix_fmt yuv420p -r 25 -an -f mov timelapse.mov
This creates a Youtube ready video file. Watch at at least the 720p setting.