How do one create a "Subscribe and notification" animation for YouTube videos in Aftereffect?

After they record the video they bring it into a video editing program, create the graphics animation on top and then they render the video out to it's final format and upload it to Youtube.  In After Effects (or Premier): the basic workflow would be to import the video you want to put the graphics onto.  Then either import pre-made graphic assets or use native shape & text tools to create the graphics, animate them by keyframing their basic attributes like opacity, position, scale & rotation, then, finally importing the .aep file to Adobe Media Encoder, rendering out a final video and uploading it to Youtube,

Here is a very basic tutorial set  on how to import a video, add stuff on top of it and then render it out. Try adding special effects to a video | 

if you want to learn AE just to create this i prefer to save your time and buy a simple MOGRT maybe from adobe stock and use it inside premiere pro and save your time doing what you do. Youtube stock graphic design and motion graphic templates | Adobe Stock

but if you want to learn after effects to enhance your knowledge, adobe website is a good place start After Effects tutorials