Not to try and put you off, the task(s) you are asking about being fairly common in LabVIEW, but there are a number of examples
under the Help pulldown in the taskbar at the top of the LabVIEW screen, "Find Examples". Give those a look and then if you still need help, restate your question (in this thread, please) to more clearly define what you are trying to do. Depending on how your text file is configured (if it is configured like a "spreadsheet" with values seperated by "delimiters", tabs or commas, and rows ended by "end of line" characters, the it can be read in quite easily using the "read from spreadsheet" function. This function then gives you an array of whatever the values were which could then be loaded into a listbox. Clicking on the entry in a listbox will return a numerical value, representing its place on the list. That number can be used to index the original array to retrieve the original array's value at that point.
P.M.
PutnamCertified LabVIEW Developer
Senior Test Engineer North Shore Technology, Inc.
Currently using LV 2012-LabVIEW 2018, RT8.5

LabVIEW Champion