How to link data in 2 excel files and combine them into 1 using macro?

FILE 1
data: Column A, B and C

FILE 2
data: Column A, and D

Use FILE 1 as the primary file.

Final Result: should have A , B C and D together in 1 spreadsheet.

Problem : Look up function but seems like it doesn't work well. the data is jumble up. I still to check using True false function. cos what is avai in A may not be found in B. 


Pri file has more information ( in terms of number of names ) than file 2.
name      data1       data2      data3

and in file 2:
name      data1       data2      data3  data4 

Macro - ADD 3 rows & UNDO Macro to undo the addition of 3 rows

To do the following :

a) ADD 3 Rows
 (or even more rows) by prompting user to enter the number of rows they wish to insert.


b) UNDO MACRO:

1. Undo the addition/insertion of rows 

2. when click, it will also prompt: "Do you want to undo adding 3 rows ?" 
> Yes | Cancel
if Yes, macro proceed and if Cancel , macro will not run and remain.

How to create a "pick from list" in MS excel?

How to create a "pick from list" in MS excel?

(something similar to combo box)