This classic Oasis track is absolutely perfect for beginners as the main part of the song essentially uses one easy chord shape with the bass note moving. It's also great for improvers on the guitar as it'll help you master a really cool, 2 bar rhythm pattern that repeats through the song.
All the chords are shown below, with the top line of chords being the first whole section of the track, and the second line of chords start to crop up as the song develops. Remember that there are other ways to fret all of these chords, so if you don't like using the thumb then try alternate versions until you find a shape that fits you!
The main rhythm pattern that you use in the song comprises of two halves, which you play on each chord. The pattern is below and can be used all the way through the track (with embellishments here and there based on the dynamics of the song). Remember: The first beat of the first pattern tends to only play the root note of each chord, rather than strum the full chord.