I am completely new to Apex and could really use some help with what seems to be a simple task.  I have a formula on the contact, Persona_True__c, that returns a 1 if the custom field "persona" is populated and a 0 if it is blank.

I would like to have a roll-up summary that sums this field at the account level in a field called Related_Personas__c.  

Because we can't roll-up from contact to account I'm reading that this type of action needs to be a trigger, but I don't even know where to start.  Does anyone have any thoughts or expertise they can share to help me out? 

I am completely new to Apex and could really use some help with what seems to be a simple task.  I have a formula on the contact, Persona_True__c, that returns a 1 if the custom field "persona" is populated and a 0 if it is blank.

I would like to have a roll-up summary that sums this field at the account level in a field called Related_Personas__c.  

Because we can't roll-up from contact to account I'm reading that this type of action needs to be a trigger, but I don't even know where to start.  Does anyone have any thoughts or expertise they can share to help me out? 

I am completely new to Apex and could really use some help with what seems to be a simple task.  I have a formula on the contact, Persona_True__c, that returns a 1 if the custom field "persona" is populated and a 0 if it is blank.

I would like to have a roll-up summary that sums this field at the account level in a field called Related_Personas__c.  

Because we can't roll-up from contact to account I'm reading that this type of action needs to be a trigger, but I don't even know where to start.  Does anyone have any thoughts or expertise they can share to help me out? 

I don't know why, but Trailhead does not see that I've setup a user Samantha Cordero with the profile Field Sales User. I've create the Field Sales User profile, created the user Samantha Cordero, activate the user, generate a password, and logged in as the user. I even logged in as her in Salesforce 1, but I still get this message:

Here is what her user detail page:

Field Sales User profile: