Excel Spreadsheet Formula

I have 2 spreadsheets. I need to reference the value in a cell on sheet 1, and look for that value in an exact column that won't be in any kind of order on sheet 2. Once the reference value is found on sheet 2, I need to reference a column on the same row in sheet 2 and return a binary answer based on whether the number is <1 or >= 1. That binary answer needs to substitute for an existing value on sheet 1, on the same row as the original reference number. I need this process to repeat automatically for every value in the same column on sheet 1, sequentially until the whole sheet is completed. I believe this will take someone that knows excel less than 5 minutes.