Learning to play guitar can be fun but also frustrating. First you need to learn the basic chord forms with your left hand for ABCDEF and G. It will take some practice but once you have the finger movements committed to memory you will be on your way to puting them together to create rhythms then eventually songs. Some basic knowledge of music theory is very helpful but not necessarily a necessity in the early stages. You will soon learn certain chords fit together such as CF and G while EA and D also fit together. The right hand picking motion is what some beginners having trouble with as it takes time develop and up and down motion for the individual strings. Once you can play through the strings fingering a chord you can progress to picking through the strings while changing chords. Learn the basic chord formations first and then work on right hand struming and picking. With some time and practice and it will not come overnight you will be able to utilize websites like guitartab and ultimate guitar to looks up you favorite songs and work on making music. It will get easier as you go along so don't get discouraged but the first six months or so will test you patience. Many people take lessons but the basic chords and fundamentals nowadays can be found online or in instrutional books at your local music store. Your fingers tips will be sore if learning on an acoustic but daily practice will toughen them up and playing will become much easier. Talk with other players who may provide tips and inspiration. They will keep you motivated when you get discouraged. BOL and don't expect too much too early but before you know it you will see some progress that will keep you eager to learn more.
Learn atleast one gratifying riff like smoke on the water to show yourself that you can learn and that learning is actually fun then start working on the chords like John Boland said.
Have taken a few guitar lessons over the past few years, but never stuck with it. Too frustrating. I decided to get Rocksmith and am taking the 60 day challenge. Halfway thru and it's working. Getting better and enjoying the practice.