Help me reinstall Gapps in my Rooted Xperia SP Recently, I rooted my Xperia SP (running on Stock Jellybean 4.3). Out of excitement, I uninstalled a few Google Apps (gapps) from my phone. But I think I require the Play Store. How can I reinstall Gapps on my phone?

Let me clearly explain you my current status → for uninstalling those apps, I used ES File Manager (Root Explorer-->Uninstall System App). Though some apps like the play store, gmail, facebook etc. were uninstalled, I found that apps like google account manager, google backup transport cannot be completely uninstalled. So, now I have an incomplete set of Gapps. I compared this list of essential gapps with my file manager's system apps' list and found only SetupWizard.apk missing. So, I downloaded SetupWizard.apk from here and tried to install using ADB but I got this error: [INSTALL_PARSE_FAILED_NO_CERTIFICATES]. Another interesting thing is that when I try to install SetupWizard.apk using my file manager, I get these screens, out of which the first screen suggests that Setup Wizard is already installed in my phone. What the heck is all these, man???

 

Now, I am a total newbie to flashing and other super-geek things, so I am pretty scared to flash the gapps' zip using CWM. Please give me an alternative way, if possible.
First of all you don't tell us what exactly apps you uninstalled there is a chance that you uninstalled some app that cannot be replaced by just adding gapps. Varius gapps for all the versions can be found here https://goo.im/gapps/ please be carefull to choose the right version according to the version of Android installed on your smartphone. 

You should not be afraid to flash .zips from the CWM, one of the reasons of root and installing a custom recovery it this one. Also it will save you a lot of time. 

If the first line of this answer is true then you will have to reinstall the ROM that is currently being used at your smartphone.