Multiple dropdowns boxes

Describe the problem.

I have a website which has 3 category links:
Cat 1 - Macbook
Cat 2 - Macbook Air
Cat 3 - Macbook Pro

After selecting a category the next page will have 3 selection boxes:

1 - screen size
option
option
option
2 - Processor
option
option
option
3 - Hard Drive
option
option
option

Scraper must make a selection form all 3 boxes for a button to display.

Then the scraper must click on the button which will reveal multiple models that matches the criteria.

Scraper then needs to click each model and scrape data on model pages.

I'm unable to get anything close to working and any help would be greatly appreciated.

Here is the url: https://www.buybackworld.com/sell/macbook