Auto Action: check multiple select items when one items is checked

Hi This is what I'm trying to achieve.

1. I have a CB field called cb_modulescompleted it has values such as Module 1, Module 2, Module 3 etc.
2. if a user has completed Module 3 then they would have also completed module 1 & 2 and those values should also be selected in the field
3. the user database has been poorly maintained an in alot of cases Modules 1 & 2 have not been selected
4. I am trying to make an Auto Action to check Module 1 & Module 2 values (checkboxes) if module 3 is selected

Auto Action Setup:
==============
Global
Triggers: onAfterLogin, onAfterUserProfileSaved
Type: Field

Conditions
Value: [cb_modulescompleted]
Operator: Is REGEX
Value: /m3/
Translate: checked
Format: checked
Prepare: unchecked

Action
Field: cb_modulescompleted
Operator: Set (Field = Value)
Value: m1
Translate Value: No
Save Directly: Yes

Now in the users section when I check Module 3 and save, the result is Module 1 is checked but Module 3 gets unchecked. Please note that I have also used the + Add Rows button to the right and did the same action values as above but changed the value to m2. When doing this the Module 2 checkbox is checked instead of checkbox 1.

I hope this is enough to go on, any guidance on this would be greatly appreciated.

Multicheckbox and Multiselect fields store as |*| delimitered. This means if multiple values are selected you'd have VALUE_1|*|VALUE_2|*|VALUE_3 for example. So you should be setting your field to m1|*|m2|*|m3 based off the information you've provided.