Chordify.net isn't usually perfect, but it is still a great tool. You just have to kind of see if what it displays matches up with what you are hearing. Looks like this song is pretty beginner-friendly.
https://chordify.net/chords/the-holdup-you-been-whinin-dubby529
Can you come up with $20 or so? Or maybe a have a birthday or something coming up?
An app is ok in a pinch, but you’re going to get much more accurate tuning with an actual tuner.
I recommend this one...
Snark ST-2 Super Tight Chromatic All Instrument Tuner https://www.amazon.ca/dp/B01H62TQ68/ref=cm_sw_r_cp_api_cFMjBbKHRGYHY
This was my first one. It's nothing special, but it wont hold you back from learning. With some half decent strings it sounds pretty good considering the price.