the best way to install Python and manage the environments is using conda. You can choose between anaconda and miniconda, the latter being preferable as it's much smaller (doesn't install much by default).
For windows, look for "anaconda prompt".
Once installed, to make sure you have the latest version, run
conda update conda`
To create an environment, do:
conda create --name my_new_env
To activate:
conda activate my_new_env
To install packages (for example, numpy):
conda install numpy
To see what you have installed:
conda list
To deactivate an environment:
conda deactivate
To view all the environments:
conda env list