Unsure about syntax for using pre-existing variables in mutation

Hello friends! I’m currently creating an integration between a CRM system and Monday, writing the backend in the CRM’s own scripting language. My question is:
I have a variable called projectName, where the name of the project that I would like to set is saved, and I would like to send in this variable in my mutation so it also gets saved as the board name for my board. Although, I’m not really sure how to write that. This is what I’ve tried, but failed:

I guess the projectName variable should light up as blue, since that’s the color of variables in the system, but I can’t figure out the syntax. Mind you, I don’t want to specify the content of projectName in the query, since it may differ for every request.
Anybody has an ideá of how I should format this query? So thankful for any help!

I resolved the issue! For anybody interested: This is how I did!