This is a pleasant little acoustic song, and a good fingerpicking workout. As long as you are already familiar with fingerpicking basics, you should be able to learn this song quite quickly. Check out the Core Skills section on Fingerpicking if you need to brush up.
If you get the hang of the fingerpicking pattern to this song, the rest will come quite easily because most of the chord changes for the fretboard hand are actually very simple. So, hold the first Gm chord with your fingers and just keep practicing the same fingerpicking pattern over and over until it becomes natural and you can go quite quickly with it. Once you have mastered that, then work on the rest of the song.
The fingerpicking pattern is T/2 - T - 1 - T - 2 - T (repeat)
Don't worry if you need to go slow, just get the pattern right. The speed will come with continued practice. The song may seem long, but it's really not so bad once you realise that the same verse sequence appears a LOT. It accounts for over 3/4 of the song's total length, so once you learn it you will know most of the song.
Verse - The song starts on the verse progression. Although it's quite long, it's mostly simple chord changes for your fretboard hand. The hardest part is the last 4 chord changes. You may wish to use alternate fingers for this part, e.g. using your thumb to play fret 2 (F#) on the Low E string. However, the fingers we show here will be the easiest way for most people.
After that 'awkward' section, just repeat the whole verse again.
Bridge - This short section is similar to the middle of the verse and uses the same fingerpicking pattern throughout. If you can already play the verse, this will be no problem. Afterwards, just play the verse again.
Bridge 2 - This is very similar to the first bridge, but be careful, some of the chords are slightly different. Ends with this ascending sequence. Then play the verse again for the last time.
End with a slow strum on the G minor chord.