Just getting a chord from a book or off the internet will provide the notes. But, how should the notes be played and which fingers should you use and why is it important?
When playing any music on any instrument you are always thinking ahead. Just as when driving or cycling you are always looking ahead and observing the road surface, pedestrians, traffic signals.
Music is the same. How something is played depends on the next notes or chord to be played.
Learn to play properly and your chances of playing smoothly will advance tremendously. Using the correct fingers will improve your dexterity when looking for the next chord. sometimes it may be necessary to use different fingers to standard. Knowing the standard fingering will ensure you are able to make those choices.
The chord of A Major is one of the most common chords you will use, along with the other major chords. Practice this chord and also change between this chord and some of the other ones I have taught you.
Now learn to play the piano chord of A minor/how-to-play-the-a-minor-chord-on-piano/