How to customize sap fiori client

My requirement is to customize SAP FIORI Client.I am new to SAP UI5; can anyone please answers to my below questions.

i gone thru different forums and found that need to download SAP FIORI Client SDK and do changes accordingly.My questions are as below.

1. From where i need to download SAP FIORI Client SDK..

2 What system logins are required to customize ( i have web ide; Eclipse & SMP logins)