How to Install Custom ROM in CWM Recovery.

ClockworkMod Recovery can be used to flash CyanogenMod ROM or any other custom ROM on Android devices. There’s a “install zip from sdcard” option that will let you install a ROM zip file on your device. Being the most popular custom recovery for Android, most users prefer it over other solutions. Also, it’s fairly easy to use CWM recovery to install CM or any other ROM. Here is the step by step guide:

How to Install Custom ROM using ClockworkMod (CWM) Recovery

This guide can be used to install custom ROM on your Android device. Not to mention that your device should be rooted and should have CWM Recovery installed. Also, please download the custom ROM zip file that you will be installing. Some of the popular ROMs are:
CyanogenMod (CM) (Latest is: CM 10.1), Modaco, AOKP, Slim ROM, MIUI. There are many other ROMs for different Android devices. You can choose the one that suits your needs the best.
Preliminary Steps:
Take care of following tasks before you proceed with flashing custom ROM:
Task 1: Install USB drivers for your device on your PC.
Task 2: Be sure to backup your data including Contacts, SMS / MMS, APN & MMS Settings as well as photos and videos stored on your device’s internal or external storage.
Task 3: Make sure that your device is well charged. Ideally, the battery level should be around 60-80%. The more the better.
Task 4: USB Debugging should be enabled on your device.
Important: Most of the custom ROM will not have Google Apps in them. So, you will have to download and install GApps manually.
Done with preliminary precautionary steps? So, here’s the guide:

How to: Install Zip from SD Card in CWM Recovery

Step 1: Download the ROM zip file and copy it on root of the SD card of your device. Also copy the GApps zip file, if you want to install Google Apps too.
Step 2: Disconnect your device from the computer and boot it into CWM recovery mode:

1. Switch off your device
2. Press & hold Volume buttons + Power button to boot into bootloader mode (Note: button combination may vary depending on your device)
3. Now select “Recovery” option using Power button to boot into CWM recovery mode

You are now in CWM recovery more. Use volume keys to navigate up & down and use Power button to select an option.
Step 3 (Optional but important): Take a NANDROID backup of your ROM:

1. From Recovery screen, select “Backup and Restore”
2. Now select “Backup” to start the nandroid backup process.

After backup is done, navigate back to main recovery screen.
Step 4: Now select “wipe data/factory reset” option. When it asks for confirmation, select “Yes” to confirm data wipe process. Then navigate back to main recovery.
Step 5: Now you will install the ROM zip file that you placed to SD card of your device in step 1. Follow these steps:

1. Select option “install zip from sdcard”
2. Then select “choose zip from sdcard”
3. Now select the zip file that you want to install (the file that you copied onto the SD card)
4. When it asks for confirmation, select “Yes” to start installation

The custom ROM installation will now begin. Wait for it till its complete.
Note: If you copied any other zip file alongside the ROM file (like GApps zip), repeat the above steps to install that zip file.
Step 6: After installation is complete, navigate back to main recovery screen and select “reboot system now” option to reboot your device.
Your device will now reboot. Please note that first boot may take some time, so be patient and do not interrupt the boot process.
When it boots up, your device will have custom ROM installed. Same steps can be followed to install any zip file like Google Apps on your device.