I have installed an app from shopify for check out. Now i want to disabe inbuilt check out page

[muskanasif]

I have installed an app from shopify for check out. Now i want to disabe inbuilt check out page. I am unable to find any option for disabling in-built checkout. At the time of check out 2 forms are available. One built and onf from the shopify store app. 

I want to disable the in-built one.

Plz guide me