A animation is basically the same as a pose. To proceed on this page, make sure you have understood and successfully worked through "how to make a new pose" on this website.
To create an animation, imagine the movements of that animation like "single poses" or "single pictures" that run in a loop, repeatedly. For example, a "nodding head" would have one pose "head bend forward" and one pose "head bend backward".
To create an animation, you make with your Animare HUD the first pose, then copy and paste it into the sample bvh file, but leave that bvh file open.
Afterwards you create the next pose, and export (copy paste) that line as well into the bvh file.
Continue as long as needed.
When you are done, you should have at the bottom of your bvh File:
MOTION
Frames: 2
Frame Time: 1
0.000000 0.000000 0.000000 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
and then your copy/pasted lines.
Now, change the value in "Frames" from 2 to as many lines that are under "Frame Time". That means, all your lines and the one with "all 0" that has been there already, count.
Afterwards change "Frame Time" to a value in seconds, how long the anim shall stay in each frame. Different speeds within one animation are not possible. You can only achieve that by having one frame run twice in a row.
The overall time of Frames multiplied with Frame Time shall not exceed 30 seconds. Otherwise, the upload will fail with an according error message.
That's it ;)
Good luck!