Populating a column in an Excel tab based on matching values from 2 columns in different tabs

This is not that hard, but you have to make some changes.

1) In tab 2, change the order of your columns, Put Column B as the first column.
2) in tab 1, on c1 =VLOOKUP(A1,Sheet2!$A$1:$B$10,1,).

In this case my tab 2 page is called Sheet2, so you need to change that and also, change the range, In my case I use 10 rows so it goes from a1 to b10. the $ symbol is to lock the values so you can paste it without problems.

Is there a way to specify an undetermined amount of rows, (instead of 10?)

To do it without flipping the columns:

=index(sheet2!a:a,match(a2,sheet2!b:b,0),1)

sure you can do it with as many rows as you want, just replace the 10 in the formula with the last row you want to search.

I've got both solutions working on a spreadsheet I just created but can't get it to work on my initial spreadsheet.

The data on tab1 does not begin until line 4
The data on tab2 does not begin until line 2

Still playing around with it...

ok, just change the initial value, in my solution something like this: =VLOOKUP(A4,Sheet2!$A$2:$B$10,1,).

Notice, I replaced the first A1 with an A4 (row 4) and the A$1 with A$2. This should work.

For matthewspatrick's solution

=index(sheet2!a:a,match(a4,sheet2!b:b,0),1)

notice, I replaced a2 with a4, where your data begins. I'm not sure if you have to change any other value.

Can you take a look at the attached spreadsheet? I cannot figure this out for the life of me.
Book1.xlsx

Change the name of the sheets on the formulas. From sheet1 and sheet2, to the name of your sheets (tabs). Also, because you have spaces in your names put the sheet name between ', example, ' sheet name'