Ok, here's the deal:
I have two spreadsheets. One is the "master" spreadsheet that needs to be
updated, while the second spreadsheet is a basic report that contains all the
most up-to-date data. I need to import the second spreadsheet's data into the
master, but the problem is that the two have different formats.

The second spreadsheet contains data organized into four columns (Column A,
B, C, and D):
A1 B1 C1 D1
A2 B2 C2 D2
A3 B3 C3 D3

However, in order to copy-paste the data straight into the master
spreadsheet, I need all the data in the second spreadsheet in a SINGLE
column. I need to convert the format specified above and put all the data
into the Column A, in the following sequence:
A1
B1
C1
D1
A2
B2
C2
D2
A3
B3
C3
D3

And so on and so forth for about 5,000 lines.

Can anyone help me with the coding for this?