inject custom js (h5p stand-alone)

[mosaleh-dev]

Hey, hope everyone is doing well, and thanks for this awesome theme
I do not know if this is where I should ask and if my question is valid or not, since I know nothing about JS
I am trying to create a math blog and I need to embed h5p stand-alone in my blog for interactive content things are not clear for me how to achieve this without putting JS files with every post I have managed to make it work in index page put posts are not working even when project files are in the same folder
thanks in advance