To Use these credentials(JWT Credentials without JWT token) and to make connection in box APIs using postman

Hi,

I Got these ID in json format. We have to make connections only using these IDs.
{
“boxAppSettings”: {
“clientID”: “”,
“clientSecret”: “”,
“appAuth”: {
“publicKeyID”: “”,
“privateKey”: “”,
“passphrase”: “”
}
},

“enterpriseID”: “”
}
the environment will be like this.
poc environment : xyz.box.com
I got the above details for our box environment. I am trying to connect from postman to box account. But unable to make a connection, facing unauthorized error like this
{

"error": "unauthorized_client",
"error_description": "The grant type is unauthorized for this client_id"

}
I have set up the environment in postman, the setup will contains the above credentials only and tried some APIs to get response but facing unauthorized error.
Do we need access token or I need to get separate user level access to make the connection ?
Can someone please help me to make connection to the box.

Can someone provide the documentation for future reference.