Triggering structures with time from my workspace in my simulink model

Hi! I am trying to find a way to trigger my signal any time i want in my simulink model. What happens is when the simulation starts, my structure with time from workspace (signal) starts together, but i need the signal to start when i push a button or something like that. I am trying not to use Variable Time Delay Block because it's not good when you're working with ERT/GRT code generation. Any ideas?