i'm looking to update custom picklists on opportunity when a sepcific user is sending an email with specific subject,
there are two user lookups on the opp, when the user in lookup A sends the email and the subject contains X, or user  B with subject Y, i'd like a picklist C or D to be updated with a value "in progress"

i found this but i cant modify to meet the above..

trigger TaskSubject on Task (after update, after insert) {
set<id> accountIdSet = new set<id>();
 
//capture all the subject names in a set
//set<string> subjectName = new set<string>{'financial review','legal precheck'};
map<id, list<opportunity>> opptyMap = new map<id, list<opportunity>>();
list<opportunity> updateOppList = new list<opportunity>();
 
//get those tasks where the tasks are related to opp, Capture the account IDs in a set.
for(task t: trigger.new){
            string tempId = string.valueOf(t.WhatId);
    if(tempId.startsWith('006')){
        oppIdSet.add(t.whatId);
    }   }
 
//If we get the opportunities then change the stage.
if(Trigger.isUpdate && opptyMap.size()>0){
    for(task t: trigger.new){
 
 //Check if the subject of the task is one among the set
 //and also confirm that the subject has been changed.
 
        if(t.subject != trigger.oldMap.get(t.id).subject && opptyMap.containsKey(t.whatId)){
 
  //iterate thru the list of the opportunity associated with that account
  //and check which of the opportunity contains the task subject in the
   //opportunity name and update the stage to qualification
 
            for(opportunity oppty: opptyMap.get(t.whatId)){
                if(oppty.name.contains(t.subject)){
                    oppty.stageName='Qualification';
                    updateOppList.add(oppty);
                }            }        }        }        }
if(Trigger.isInsert && opptyMap.size()>0){
     for(task t: trigger.new){
            if(opptyMap.containsKey(t.whatId)){
                for(opportunity oppty: opptyMap.get(t.whatId)){
                   if(oppty.name.contains(t.subject)){
                      oppty.stageName='Qualification';
                      updateOppList.add(oppty);
                   }              }            }         }        }
//update the oppties
if(updateOppList.size()>0){
    update updateOppList;
}     }