Adding custom text & blocks to Category Archive

Hi,
I would like to add custom text to a category archive.
And it would be good to use the different content blocks to display and filter the right posts from sub-categories.

For example, a category & sub-categories are called:
Spain
– sights in Spain
– food in Spain

In the category archive I would like to add my own text with more info about sights & food in Spain.
Then in that content I would like to place a block filtering the posts with the sub-category “sights in Spain” and beneath the food text the posts with the sub-category “food in Spain”.

Where & how can I do this?

Thanks!