I realize that you are new to this, but what you are asking is akin to going to a French cusine website and asking how to fry an egg. There is nothing wrong in not knowing how to fry an egg, nor is there anything wrong in not knowing how to create a text file. Yet those are basic questions that more appropriate to be learned from YouTube videos, internet tutorials, books, etc.

You can create a text file in your favorite editor that exists in your GUI environment (Windows, iOS, Android, etc) and upload it to the Linux server. Or if Linux is sharing the same computer with your GUI environment, simply copy the file into your Linux directory.

Linux has text and graphical editors, but I don't know which Linux you are using. It is a safe bet that you have nano editor, so you type:

nano samples.txt

That will open an editor window, where you can type or paste file names, and maybe with the directory prepended to them (for example, RAW_DATA/my_file_1, RAW_DATA/my_file_2, etc). When you are done, save the file by typing "CTRL+X" and that should do it. It may work if you type gedit samples.txt in which case a graphical text editor will open. If that works, those editors look like most other GUI point-and-click text editors.