5 control points for picture 1&2,
5 control points for picture 1&3,
5 control points for picture 2&3,
5 control points for picture 2&4,
5 control points for picture 3&4.
Remember after selecting the first control point, the subsequent points will be easy because the computer will try to suggest the correct spot for you. Also u should use the "finetune" button to get more accurate alligning.
After that must select "optimze now" for both optimizer and exposure to achieve a constant exposure.
If have pictures with vary exposures, you should anchor the picture with right exposure under "images", under the button call "anchor image for exposure".
Finally go "assistant" to use the align and you will see the result, the smaller the standard deviation, the better. Mine came up as " very good fit statement"