How to access a specific item of a list

I used this website(http://appinventor.pevest.com/?p=490) for my app that is simply supposed to get a file(a list of latitude longitude coordinates) from an arduino mega then take. But it does not show how to access each column. I am looking to read a file then plot the longitude and latitude separately.

I hope I am clear in what I am trying to do. But in case its not then I have a simple example showing what I want to do. 

File example:

32.3459,88.0439

32.3458,88.0438

.

.

.

App reads file and parses it. Something like it

longtextbox: 32.3459

lattextbox: 88.0439

then it reads the next line

longtextbox: 32.3458

lattextbox: 88.0438

...and so one

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you might want to ask the author of that example there http://appinventor.pevest.com/?p=490

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Read the file into a list from csv table block.

Then get a row of lat,lon with select list item.

From that row do another select list item where the index is 1 for lat value, and 2 for lon value.

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