Merging two separate csv files with different fields

I am new to Pentaho and this forum and I have browsed for an answer.

I have two separate csv files with different fields that need to be merged.

For example CSV1 has the header names: Part_No, Serial_No, Time_stamp. For this example, call it 3 fields.

And CSV2 has Test1, Value1, Test2, Value2, Test3, Value3, etc. And here let's limit this to 6 fields for this example.

I would like to merge so CSV3 looks like: Part_No, Serial_No, Time_stamp, Test1, Value1, Test2, Value2, Test3, Value3, etc.
I do not want to lose the header / field names if possible.

All the rows of data below the headers are on a correct 1:1 relationship so I do not have to worry order.

Any help would be appreciated.