How to load the unity content on button click ?

In webGL build I have created a progress bar and a button on html page,once the progress bar is full the button will appear.
On clicking the button the unity content should load.

But, Once the progress bar is full the unity content is running in background.
How to control loading of the unity content on button click??

Have a look at this:

Set timeScale to 0 - It will cause the time inside the game to stop running, essentially pausing everything. Setting it to 1 will resume the game. So you can toggle it to 0 when the progress bar is done, and back to 1 when the user clicks on it