Organizing Products

Hello,
I am new here and this question is probably silly, but still I’m a bit tired now. I was wondering…
Q: How can I organize my products in the correct categories?
EX: Dresses show up when I click on TOPS

Also I can’t seem to create a new window/page for each category
EX: I have windows for
-HOME
-SHOP
-SALE
-CONTACT US
but I cant create windows/pages for the categories under the main menus:
EX:
-SHOP
-Dresses
-Tops
-Bottoms
Every time I click on any of those it will show the SAME page and it will MIX my products.

Please help me with these problems, thank you.
If possible I would prefer STEP BY STEP instructions rather than codes. Thank you.
🙂