install cwm recovery in a softbrick android phone My Android device is not booting up and is stuck on the manufacturer's logo.  The phone was rooted with Kingo-Root and Clockwork Recovery Mod wasn't installed.  Now I want to unbrick my phone with custom rom flashing.  So I think I need to install CWM recovery although my device is not booting - is this possible?  Also, if I want to flash a stock ROM - do I need to unroot my device first?  If so, how can I unroot it if it's not booting?
You can go ahead with what you are planning. Find a suitable Clockwork Mod recovery for your device.

Boot your phone into fastboot mode using key combinations which differ from device to device. The common ones are Power Button+Volume Up or Power Button+Volume Down.

If you had ever unlocked your device's bootloader, skip this step. To flash a custom recovery, you need your bootloader to be unlocked. To unlock it, after booting the phone into fastboot mode, connect it with PC via USB, download platform tools for android, open cmd, run the following command in the directory where you have placed the platform tools:

fastboot oem unlock


Keep in mind, this will delete all your internal storage, plus void your phone's warranty.

Once the bootloader is unlocked, place the recovery file in the platform tools directory and rename it to recovery.img for convenience.

Run the command:

fastboot flash recovery recovery.img


This will flash the Clockwork Mod recovery on your device and you can flash any desirable ROM.