First, configure the Netsuite with this by giving the Account ID, ( which we get from Setup>Company>Company Information)
Then configure the Bigcommerce
To configure this we should have a Client ID, Acess token, and Store hash ( all 3 are provided by the client, in the case of the test account we can generate this)
Then click on the Integrator Bundle Install option
Thus the bundle gets installed in Installed Bundles List.
Then click on the Verify Now option
Then click on the Install option of Bigcommerce Bundle
After the bundle gets Installed, click on the Verify Now option of the Bigcommerce Bundle
Now the Installation process is complete.

