How the hell you do eat someone out???

Me and my girl friend have been together for about 2 months but we’ve liked each other for 4 years prior and we’ve been friends since I was 3. We’re both still in high school and I’m extremely inexperienced and she’s only dated one guy. We make out and stuff but have never gotten any farther than that and I’m the dom so naturally its gunna have to be me that initiates something and I have to clue how to do this. Please help!!!