I have two columns B2 (10/01/2019) and C2 (01/22/2019) and I need to figure out what formula to use in order to make these reflect 30, 60, and 90 days. B2 has various dates but C2 is like a due date.
And I can't even speak excel [...] I've been told to use conditional formatting
You certainly could be clearer about your requirements. You don't have to "speak Excel". But I think you might want something like the following.
First, the formula =B2-C2 gives the number of days between dates. You might set up Conditional Formats that will fill B2 with red, orange, or yellow if it s 90 or more days, 60 or more days, or 30 or more days after the date in C2. Here is one way.
1. Select B2.
2. Click Home > Condition Formatting > Manage Rules.
3. Click New Rule > Use A Formula..., and enter the formula =B2-C2 >= 30 into the field labeled "Format values where...". Then click Format > Fill, select the color (yellow), click OK > OK, and select "Stop If True".
4. Repeat
#3 two more times, replacing 30 with 60 and yellow with orange, then replacing 30 with 90 and yellow with red in the instructions.
5. Finally, click OK to exit the Conditional Formatting Rules Manager.
The order of the rules is important. If you follow the above instructions exactly, the order should be correct: >=90, >=60, then >=30. If not, select each rule and click the up-arrow or down-arrow to correct the order as explained.
Test the conditional formatting by entering the following dates into B2, with 1/22/2019 in C2: 2/20/2019 (less than 30 days; no fill), 2/21/2019 (30 days; yellow fill), 3/22/2019 (less than 60 days; still yellow fill), 3/23/2019 (60 days; orange fill), 4/21/2019 (less than 90 days; still orange fill), 4/22/2019 (90 days; red fill), 4/23/2019 (more than 90 days; still red fill).
You can use the Format Painter to copy the format to other cells in column B. Select B2, click Format Painter, then select the cells in column B.