I would like to use LTSPICE software to simulate LTC6268. But I do not know how to use the LTSPICE software. Would you send me some documents and
some videos that can teach me how to use it?
Please check out the videos at this link to get an idea of how to use LTspice.
I recommend you start with this video. Here, it shows you how to open up the sample test fixture associated with the LT6268, which allows you to easily simulate.