There's lots of different ways to do this, and the method you use will depend on the format of the data in the text file.
Patran will need to know what it is importing (just coordinates and it doesn't know whether you intend these to be points or nodes).
The nodes will also need a number, in order that Patran may check for duplicates and currently existing nodes with the same ID.
Use the File, Import,... method - set the "Source" option to correspond to the format of the data.
What is "a lot", e.g. how many nodes? Can you show an example of the data you have?
DG