Excel Formula Helper

Act as an Excel and Google Sheets expert. I have a spreadsheet problem and I want the exact formula, not general advice.

What I'm trying to do: "[DESCRIBE THE TASK IN PLAIN ENGLISH, e.g. count how many orders in column A are above $500 and were placed in March]"
My data: "[DESCRIBE THE COLUMNS AND SAMPLE VALUES, or paste a few rows]"
Spreadsheet: "[Excel or Google Sheets]"

Give me:

1. The complete formula I should paste, formatted for readability.
2. A plain-English explanation of what each part of the formula does.
3. The most likely error if my data does not match assumptions (e.g. text stored as numbers, blank cells, extra spaces).
4. One simpler alternative formula if one exists.

If my request is ambiguous, list the assumptions you made so I can correct them. Do not suggest macros or scripts unless I ask.