Thank you for reaching out.
You can use the PQL function ACTIVITY_LEAD to find out where each process will go in the next x process steps. You can use ACTIVITY_LAG for the previous process steps respectively. The function
ACTIVITY_LEAD("ACTIVITY_TABLE"."ACTIVITY_EN", 2) for example gives you the activity which occurs in two steps. If there aren’t previous activities, it returns null. You just have to enter the activity column and the numbers of activities you want to “lead” (the default would be one).
You find a detailed description of these functions and examples in the PQL Function Library of the Celonis Cloud Help Space.
I hope this helps you in creating your analysis.