Howto: installation on Windows

Following Jeremy post for custom installation in windows 10 with Nvidia GPU, I am stuck at conda env update
I did below steps,

  1. Already have Anaconda with Python=3.6 and Git.
  2. Opened Anaconda Prompt as admin
  3. Did git clone https://github.com/fastai/fastai.git'
  4. then cd fastai/fastai in which environment.yml is available.
  5. then when I do conda env update I get below error.
 ResolvePackageNotFound:
  - spacy

then based on few answers in above posts and in this link Lesson 4 - OSError: Can't find model 'en',
I ran below two commands and installed & downloaded spacy model successfully

pip install spacy
python -m spacy download en

then when I try to run 5th step again to proceed, I get same ResolvePackageNotFound spacy error. Other people are facing this problem when they run lesson4 notebooks, but I am facing during initial installation itself. Even after installing spacy why am I getting this error, can someone tell me how to proceed further? I have already went through most of the posts available and have been stuck for many hours on this issue.