Thanks! That was quite helpful 
.But when I analyzed the data as an example, I ran into a problem.My experiment was an event-dependent design, and in some runs, some conditions did not appear. This makes when I run nilearn.glm.first_level.FirstLevelModel.com pute_contrastsg, an error has occurred: t contrasts should be length P=18, but this is length 20. How can I solve it?
In addition, I have a question about what should be inputed in SecondLevelModel.fit. I did first-level analysis of data on afni, and I ran into this problem when I wanted to do a further analysis at nilearn. In fact, after performing the first level analysis on nilearn I was also confused about what to input for the second level analysis. 
Thank you in advance for your input and patience with a newbie.
CFZ