You can use the apply log file command from the tools menu or paste in the Verbatim logger to apply markers from various text files. Simple separate lines of text with timecode and then you can apply the text as markers.
Another option is to use the Verbatim Logger and the Notes field. If the Notes field contains timecode on one line then a line of text on the next the verbatim logger will import that, then when you press Apply it will convert that to markers. (Conversely, if you have markers and go into the verbatim logger, you can press Save Text to move the markers to the Notes field instead.)