Upload or Uploaded it?
As soon as you upload (or uploaded) it on YouTube, Please share the link with us on Facebook.

Question

Answer

As soon as you upload it on YouTube, please share the link with us on Facebook. or 
As soon as you HAVE uploadED it on Youtube, please share the link with us on Facebook.

Answer

You can kinda use both, BUT if you use "uploaded" you need to use the helping verb "have." So you could say either:

As soon as you upload it on Youtube, please share the link with us on Facebook.

OR

As soon as you have uploaded it on Youtube, please share the link with us on Facebook.