Append to Array Variable

I'm retrieving data from Supabase using the Get Row node. I want to loop through the results and create a string with the relevant fields (something like: "<<firstname>> <<lastname>> will expire in <<days_until_expired>> days". I can do this when using the Log Message to Console without a problem. I want to store these strings in another variable (probably array) but I don't know how to append to an array variable. I keep getting "undefined" or "Cannot read properties of undefined (reading 'push'). How does one append to an array variable in Buildship? I can't find any documentation on it and the AI keeps returning results that don't work. This should be super easy, but maybe there's a different/better way to do this in Buildship. All I want to do is create the resultant list of formatted strings and either send an app notification or send an email with the results. Thanks in advance!