http://www.idownloadblog.com/2014/10/22/how-to-install-cydia-on-ios-8-video/
Just remember guys... Cydia substrate isn't updated yet for iOS 8 so most tweaks / apps wont work until it is.
Step 1: Jailbreak iOS 8
Step 2: Install OpenSSH on your device from the Pangu app
Step 3: Download and install CyberDuck SFTP client
Step 4: Find your iOS device’s Wi-Fi IP address via Settings → Wi-Fi → ‘i‘
Step 5: Launch CyberDuck and connect to your iOS device’s IP address
Step 6: Download the needed Cydia files, and place them on your iOS device via CyberDuck
Step 7: While CyberDuck is open, click Go → Send Command and paste the following command and click Send:
dpkg –install cydia-lproj_1.1.12_iphoneos-arm.deb cydia_1.1.13_iphoneos-arm.deb
Step 8: Click Go → Send Command again, and type restart and click Send. This will reboot your iOS device.
Upon reboot, you should see the Cydia icon on your Home screen. Launch Cydia to initialize and enjoy your new jailbroken iPhone with Cydia!
Just remember guys... Cydia substrate isn't updated yet for iOS 8 so most tweaks / apps wont work until it is.