Question about data structuring

[D Y]

Hello everyone, I am new to using mySQL and I am a bit lost. I would like to store data structured in multiple categories like this...

Category 1:
- Category ID
- Description of category
- Items
--- Item 1 w/ corresponding item ID
--- Item 2 w/ corresponding item ID
--- etc...

Category 2:
- Category ID
- Description of category
- Items
--- Item 1 w/ corresponding item ID
--- Item 2 w/ corresponding item ID
--- etc...

How would I represent this data with mysql? Do I make each category a separate database file? Or can I use tables to represent each category? How do I represent an item array in a table? And how do I link another array of item ids to the item array (such that when I need to sort the item IDs, the item list are also sorted)?

Thank you.