What are the most important data analyses that must be done in SEM-AMOS or SEM-SmartPLS for PHD data analysis?
Re your objectives mentioned above, you can perform the following data analyses:
Measurement model evaluation to analyze confirmatory factor analyses, convergent validity & discriminant validity for each of your constructs.
Structural model evaluation to analyze variance explained & path coefficients based on your hypotheses developed e.g. how "leadership styles" impacting "employee performance" etc.
Mediation analyses using e.g. Sobel test, Boostrapping etc. - these analyses are for your hypotheses e.g. how "employees' motivation" mediating the relationship between "leadership" and "employees' performance" etc.
In case you want to see how to perform the above analyses in motion, you can search from YouTube for both SmartPLS & AMOS. Wishing you all the best.