Hi, to fix your Total Blocking Time you need to defer all javascript and css assets to the end of rendering.
For example take a look at your theme.js script include, and change it to add the defer attribute so it appears as follows:
This will mean it gets loaded at the end of execution, thus freeing up rending and stopping blocking.
This is all good for JavaScript - although the trouble here is with removing render blocking on CSS because this will cause a flash of un-styled elements first while the styles are loaded. Which doesn’t look so great!
To fix the css render-blocking, you will need to inline your base styles which are required for the first render.
For achieving this you simply need to copy-paste the styles used to render your header, and home page content into a block in your header. You can find these in your developer tools under the coverage section.