First of all install virtual environment for your PC (for Windows you need to download virtualenv: check http://pip.readthedocs.io/en/stable/installing/#do-i-need-to-install-pip)
apt-get install python3-pip
pip3 install virtualenv
Create a folder for your virtual environment
mkdir venv
cd venv
virtualenv myvenv
Activate your virtual environment
FOR LINUX:
source myvenv/bin/activate
FOR WINDOWS:
myvenv/Scripts/activate
To install requirements for project go to the base folder which has requirements.txt in it, open terminal and type
pip install -r requirements.txt