Before making any call to a REST API in HOPEX you need to get an authentication bearer token. This token will allow you to access the data based on your credentials. Prior to continue make sure you have at leat the there following information :
the login of the user
the password of the user
the absolute idenfier of the environment you want to access to.
To get a token make a REST API call to the following URL
https://<<my server here>>/UAS/connect/token
You can make this call with a tool like Postman for instance. the request will be a POST request to which you will provide a set of parameters in the body.
Selection for the body option : x-www-form-urlencoded