Sq'Ukuleles are designed to be tuned to standard Ukulele tuning i.e. G4 C4 E4 A4. If these letters don't mean anything to you, don't worry, its a nomenclature that musicians use to uniquely identify notes. I like using a tuning app. You can find a ton on Google Play, but I like apps that don't require the internet. So, I download an app, turn off my internet and see if it still works (turning the internet off helps eliminate "nags" during use).
Currently I'm using gStings. Once you have gStrings downloaded onto your device, open it up and click on the green Man button. This (will strangely) turn it into Auto mode. Play one string at a time starting with the top one. Adjust the tuner until the needle is at G4. Its doesn't have to be exactly on, but within 2-3 ticks will be fine. Once you've tuned all of the strings, go back and recheck them. Often strings will detune as you tune the others. This is especially true with new instruments.
Currently I'm using gStings. Once you have gStrings downloaded onto your device, open it up and click on the green Man button. This (will strangely) turn it into Auto mode. Play one string at a time starting with the top one. Adjust the tuner until the needle is at G4. Its doesn't have to be exactly on, but within 2-3 ticks will be fine. Once you've tuned all of the strings, go back and recheck them. Often strings will detune as you tune the others. This is especially true with new instruments.