what is targets.txt file in codelink R package

Question

[AHW]

I am new to R and codelink package.

I upload two sample files using

f = list.files(pattern = "TXT")

and get the expression and SNR intensity by running first

codset = readCodelinkSet(filename = f)

I get expression by

exprs(codset)

and SNR by

getSNR(codset)

However I failed to get the Probe ID. I think I am missing something down here

pdata = read.AnnotatedDataFrame("targets.txt")
codset = readCodelinkSet(filename = pdata$FileName, phenoData = pdata)

What is targets.txt and how to prepare it? How to get probe IDs. Help appreciated