What is prerequisite to install the SSRS?

There are certain prerequisites to install the SSRS:

You should install the Microsoft .net framework 4.6.1 in order to install the SSRS 2017 edition.

SQL SERVER should be already installed on the same machine or another machine.

A user/Service account with proper access (administrator preferably) to the machine where you are going to install the SSRS.

SSRS should kept separate from the installation where your SQL Server is already installed. Both SSRS & SQL SERVER are high memory consumption services so its always a best practice to install SSRS in another machine/server.

As SSRS during installation install the database as well, make sure that ports to the SQL SERVER machine is already open. Also, as we need to connect with reporting services URL for deployment perspective, we should also open the port 80 as well.

Now if you wanted to use the subscription services of SSRS, make sure that corresponding email port and shared drive connections are readily tested.