Not sure how to help, it's term for a distinct sound playing specific notes simultaneously. I think there is 4, Major, Minor and 2 others. I forgot what lesson I was reviewing, it said something like that in the tips section. In the tips it said to remember the different sounds of each to help develop the ear, like remember how it sounds. Maybe the 4 thing was from something else. I think I got confused reading it the other day.
1-3-5 is the Major chord triad formula, the Minor is 1-2-5 so the 3 became a 2 and made the chord sound minor.
In many chords some of the notes double up but the main notes if played by themselves make up the sound.
If you use a low note you want to start with and do the formula stuff, through it could help/figure out the notes of the rest of the chord you would like that's possible.
I've been using the Ionian mode pattern when I try to count the formula but this stuff still a bit complicated for me.
Later altering the 1-3-5 makes different things, it could be strummed, plucked or played in succession.
Practicing to a Major sounding backing track maybe helps too with hearing the sound.
The middle note from the 1-3-5, the 3 if I remember often determines if the chord is either Major or Minor.
Major has a somewhat uplifting sound and Minor somewhat the opposite.
I think the 4 types are Major, Minor, Augmented and Diminished
If you see chords progressions like V-I-ii or something with letters like that, the big letters mean Major chord and lower means Minor, I think the small circle means Diminished and Augmented means altered somehow like Sus2 or Add9, I'm not too sure on the Augmented.