git-lfs init and track file from existing repo

[Daniele Simonetti]

I read this tutorial but i don't understand wich step i can skip if i use Sourcetree.
If i have an empty repository on BitBucket with Allow LFS enabled, i clone it from Sourcetree. 
Next, do i have todo 

# initialize Git LFS 
$ git lfs install
$ git lfs track

 ?