Main Menu not opening first

Hi, When the game opens it shows the splash screen unity and then directly comes on the level 1 not opening the main menu I build the main menu and also added in the build settings but I don’t know what is going on please help me regarding this.

Which scene is listed first (index 0) in your build settings page?

Yes, it works thank you one more thing I set up the interstitial ad code and attach within the game over the UI restart button but when I click on the restart button ad not working please help me regarding this. Banner ads are working properly can you please let me know about an interstitial ad that how we can attach with restart button that when user click on restart button then interstitial ad run please help me regarding this. I am waiting for your reply.

I am waiting for your reply. please help me with this.