For plotly, you probably need to open up the "anaconda prompt" from the start menu, and run:
conda install plotly
or, if that doesn't work, try:
pip install plotly
Plotly is a web-based service though, so you'll also need to register an account with them. See: https://plot.ly/python/getting-started/
--
For pyplot -- I think that should have been installed as part of matplotlib, so it should already be installed. You may need to put something like this:
import matplotlib.pyplot as plt
at the top of your code though. See: https://matplotlib.org/users/pyplot_tutorial.html