Problem with input of two files

Dear collegues,

I am relativly new in BizTalk world and that is main reason why write this posto on forum.

Currently, I have a issue with BizTalk for which need some help. The core of that issue is acctually processing of two files which I have as a input and from which BizTalk must make one file as output.

Process is:

1. Customer upload to files on FTP server , one file is Order header and second file is Order lines (both files are in CSV)

2. BizTalk must pikcup that pickup that orders.

3. BizTalk based on that two files (Order header + Order Line) must make one file which will be pick order for warehouse system

4. BizTalk send XML out of system to FTP server where WMS system can pikup that.

My question to you. How on the best manner can carry out this process in BizTalk. Which controls is best to use to achive this.

Thanks in advance,

Junior BizTalk consultant