Need help in setting Fiori Lauchpage

Hi,

First of of all .I am new to SAP technology.

We have developed story in Lumira which we can access using below URL. 

<host:port>/sap/bi/launchpad/

And by just adding word fiori at the end of URL,i can access get into Fiori launch page.

<host:port>/sap/bi/launchpad/fiori

Here I need help to change theme of Fiori launch page. I have read few blogs and its been mentioned in most of places to use theme designer to do the same.But i do not have theme designer and I am not sure how can i get it.

I want to ask is there any other to change theme of fiori launch page.Either by changing source code or using SAP Web UI IDE ( i have downloaded trial version )  or any other way ?

Please suggest me on this.

Regards,

Mukta