introduce static data

[zopiro00]

Description

I'm having problems to introduce static data with the app. I understand that it is as simple as change the name in the selector and then introduce the value in the static line but it's not working.

Steps to Reproduce

1. [First Step]
2. [Second Step]
3. [and so on...]

Expected behavior: [What you expect to happen]
What I expect is to get a static value, for example:

{
"selector": "input[name"lastname"]",
"static": "garcia"
},
Actual behavior: [What actually happens]
I just get a ramdom value.

Any idea of what i am doing wrong?
Thank you very much.
Please, this is one of my very first time trying to apply modifications in a extension or using js, so be pacient with me. Tahnk you