Expanding category with several meta field

I am currently working on developing a template for a website that will basically act as web-TV provider. My client is a television show/series producer who produces several types of programs and content in television format. They produce programs that are broadcast on one of the largest Norwegian television channel NRK.

Has built a 'custom post field' for only the video content (with YouTube video service) and is well to say done with the part. Now that I’m trying to set up a solution for the categories and have the basics ready, but need to expand the standard layout of meta fields category.

Want to add more meta-field like 'seasons', 'production year', 'total number of episodes' and the opportunity to upload some pictures as 'logo' and 'preview'.

The problem I’m struggling with now is that I have trouble getting extended with these meta-field that does not work. Have googled for several hours after working examples that I can extend the 'functions.php'. Of the examples I have found I am not happy when they are not complete or does not work. Finding good selection of plugins that can meet the need, but I’d rather have full control code in 'functions.php'.

Maybe I google with the wrong keywords that are not revelant to what I am trying to find. Or, I hope not, I’m doing something wrong, but have spent so much time that I can not solve the problem.

Here is it couple of links I’ve tried so far:
– https://wordpress.stackexchange.com/questions/689/adding-fields-to-the-category-tag-and-custom-taxonomy-edit-screen-in-the-wordpr
– https://sabramedia.com/blog/how-to-add-custom-fields-to-custom-taxonomies
– https://www.deluxeblogtips.com/taxonomy-meta-script-for-wordpress
– https://www.wpmods.com/adding-metadata-taxonomy-terms/

Would be very grateful if someone can help me with a working sample code. Or at least can point to a url with example that works with the latest version of WordPress.

I hope the post was understandable enough (translated with Google Translate).