You need an API key from https://www.pexels.com/
And you need to install the 'pexels_api' python package in your TD environment, here is a guide https://github.com/raganmd/touchdesigner-sop-to-svg (but instead of 3.5 is 3.7 and instead of svgwrite is pexels_api.
If you want to see how this was done, there is a full walkthrough video in another post.
If you have problems in the installation, write me through discord.