If you have a spreadsheet like this:
*|    A|      B|
-|-----|-------|
1|Chris|Newland|
2|John |Smith  |
And you want to join two (or more) columns to create a spreadsheet like this:
*|    A|      B|            C|
-|-----|-------|-------------|
1|Chris|Newland|Chris Newland|
2|John |Smith  |John Smith   |
Then you can create column C using a formula like:
=A1&" "&B1
The ampersand (&) operator joins (concatenates) two strings together.