Simply put the phone into recovery mode. Power the phone down. Pull the battery and replace it.then hold the volume down button. Press the power button but continue holding the volume down button.
Once the bootlolader screen appears, press the volume down button repeatedly until you highlight the recovery option. Once highlighted, press the power button to select it.
If you have the stock recovery, you will see a triangle with an exclaimation point and/or an android with a door open showing the insides. Been a long time since I've seen it.
If you have a custom recovery it will say (hopefully) 4ext recovery or twrp recovery. Possibly clockworkmod recovery. There will be many options to select, whereas there will be nothing to select in the stock recovery.