I’d advise highly to avoid ticking these options. These are experimental and may cause bootlap problems. Do Not enable app sharing and data sharing feature. I know you have not yet installed 2nd ROM but enter the name of the ROM you plan to install (anything as name – This is used for your sake of easy identification)
(This is required for Google Play Store and other Google services) Download gApps package from here and copy it to your phone.I suggested this particular ROM here as this build/port has the least number of bugs out of all AOSP/CM based KitKat ROMs) The installation process is same as for this ROM given here. (Download the latest one based on modification time – do not extract zip file) (Instead of CM11 ROM for I9500, you can also download any other ROM of your choice for your phone. Download CM11 ROM for I9500 from here and copy it to your smartphone.Download RomSwitcher app from here and install it on your phone.
How to flash Android 4.4.2 CM11 on Samsung Galaxy S4 and dual boot with Touchwhiz based stock or Custom ROMs. Make backup (full backup through recovery in case something goes wrong.).(If your s4 is not rooted, follow this guide) In this guide, we’ll show you how to install CM11 or other Android 4.4.2 based KitKat ROM and easily switch back and forth with Touchwhiz based stock or custom ROM running Android 4.3 or older: Thanks to RomSwitcher app, you can easily switch to a different ROM on boot. With the ability to install multiple ROMs on your galaxy s4, you can easily try several ROMs and finally settle onto the most preferred one. This is where the concept of dual boot comes. However, these ported builds are not fully free of all bugs and therefore should be used in conjunction with Samsung touchwhiz based stock or custom ROM. CyanogenMod 11 ROM has its base android version as KitKat 4.4.2.
Samsung has not yet released official stock Android 4.4 KitKat firmware but independent developers have ported CyanogenMod 11 for Galaxy S4 (I9500) exynos octa core variant phone.