Good evening, 

my second post today...
so I'm trying to create a trigger that will update the status of a custom object (Sales_Order__c) based on if a related task is open or if task is completed:
Open Task > Update Sales Order Status to "Pending Question"
Completed Task > Update Sales Order Status to "Sales Order Revised"

I'm not close to being a developer, so some of my coding probably has some major flaws:

trigger SalesOrderUpdateonTask on task (after insert, after update ){
set<id> Sales_Order = new set<id>();
for(Task ts : trigger.new)
{
Sales_Order.add(ts.whatid);
Sales_Order =[Select status__c from Sales_Order__c  where id in :Sales_Order];
if(String.valueOf(ts.whatId).startsWith('a1M')==TRUE)
{
Sales_Order__c.Status__c='Pending Question';
update Sales_Order;
}
}
}

On save, get a compile error: illegal assignment from List <Sales_Order__c> to set <id> at line 6...also, have another trigger to Update on task completion:


trigger SalesOrderStatusUpdate on Task (after update)
{
List<ID> Sales_Order = new List<ID>();

for(Task t: Trigger.new)
{
if(t.status == 'Completed')
{
Sales_Order__c.add(t.whatid);
}
}
Map<ID, Sales_Order__c> objMap = new Map<ID, Sales_Order__c>([select id, status__c from Sales_Order__c where id in :Sales_Order__cIDList ]);
List<Sales_Order__c> objList = new List<Sales_Order__c>();
for(Task t: Trigger.new)
{
if(t.Status__c == 'Completed')
{
Sales_Order__c so = objMap.get(t.whatid);
so.status__c = 'Sales Order Revised';
//update remaining fields.
objList.add(so);
}
}
if(objList.size() > 0)
update objList;
}

not sure how to change the variable Sales_Order__c IDlist on line 12 where it will accept, and how to combine the two triggers together into one.  Again, excuse the basic errors since i'm not a developer, but trying to find existing codes that is similar to what i'm looking for.  Thanks once again.