Learning how to read a chord is a valuable lesson. You will see these in many guitar lessons, books or could be handed one by another musician to play a song you have never played before.
The time signature is at the start, 4/4 in this case, meaning there are 4 four quarter notes per bar, i.e. 4 beats per bar.
The bar lines split up the bar, think of them as a period/full stop in writing. They are there to show you the start and end of a bar, so basically are ignored.
In the top example you will see the chords are within the bars. This just shows you what the chords are and when to change them. In this case every 4 beats.
In the lower example the chords are above the bar. So extra details like a melody or rhythms can be written into the music stave. In this example there are 4 slashes, showing you there are 4 beats per bar.
Not shown in either example is what to play in terms of rhythm or style. This is often the case and it's up to you as the guitar player to come up with a part that is suitable to the piece. This would be evident by listening to the song or in the case of a session/recording talking to the writer of the song and doing a few practices first.
A chord chart is a basic map of the song; how you get through it will be up to you.
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