Concatenate using macros and do vlookup into .xlsm file

Hi,

I need help and code to Concatenate 2 columns in both excel attached using macros and the result should be stored in new .xlsm file.

Steps:
1.) ECC_GL_Masters (base file) -- ChAc,G/L Acct , need to be Concatenate in C column
2.) BW_GL_MASTERS.XLS -- CHRT_ACCTS,ACCOUNT, need to be Concatenate in C column
3.) Vlookup Concatenate Column C of both excel into a new .xlsm file.

Hello,
Can some one help me with the code, its quite urgent. Thanks

Maybe show what you would like to see as your expected result.