On the start menu select Reporting Services Configuration Manager located under the menu
Microsoft SQL Server XXXX -> Configuration Tools, where XXXX is the version of SQL Server eg for SQL Server 2017:
In SQL 2008,2008r2, 2012, 2014, 2016, 2017 and later
Click on Windows Service Identity this identifies the reporting service Name
IN SQL SERVER 2008/2008R2
Assuming you know the computer name or domain name or IP address you would connect to the report server as follows
http://<computer name>/<report server service>
looking at the above screen shot you can see the <report server service > is ReportServer, this is the default names for all versions of SSRS.
Lets assume the domain name for the computer is www.ServerName.int, and IP address of 192.168.1.203 you can connect as either
http://www.ServerName.int/ReportServer
http://192.168.1/203/ReportServer