It's hard to tell what part you are having trouble with, so I'm just going to take wild guess. Assuming you have a checkbox in each column, like:

<input type="checkbox" name="T1" value="row1">
<input type="checkbox" name="T1" value="row2">
<input type="checkbox" name="T1" value="row3">
...
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in perl, you would get a list of the values for which the checkbox is checked by @values = CGI::param("T1");