For now, you need a free chromatic tuner app and watch a youtube video or two on how to tune a cello with a tuner:



Just make sure that IF you have to use the pegs to tune, you push in the peg in as you turn it.

It took me awhile to get comfortable tuning string instruments but once you learn how, it's not that bad. We use a tuning fork and do the rest by ear these days but at the beginning, we used a free tuner app and that was good enough until DD's ears could detect that it wasn't exactly right.