Cool to see that the Sound Professional ADC>Samsung phone adapter seems to work well.
Although maybe more information than you were asking for, here's a bit more about what the others are looking for in determining that the waveform looks fine-
"Brickwalling" is a form of analog clipping that results from incorrect gain-staging. Its a form of radical, unintended and unwanted dynamic limiting caused by overdriving an amplification stage, typically the input stage of the recorder. In the photo you posted above, it is immediately apparent that the waveform is not brickwalled because it is "hairy" looking - the peaks appear both fully extended (tall) AND are all somewhat different in height. If it was brickwalled or heavily limited, all the "hair" would be shaved or lawn-mowered off above a certain height. None of the peaks would extend beyond the point at which the amplification stage becomes completely overloaded, unable to produce a higher level output. The waveform would instead look completely flat across the top and bottom edges, and would appear much denser. And it will sound very distorted anywhere the brickwalling occurs.
Intentionally applied limiting will also "shave the hairs off" above a specific level, but the waveform will not appear much denser. When used correctly, most of the peaks will top-out below that level and only small number of them that would otherwise extend far above the others are chopped off by the limiting. The waveform will not appear much denser. When used correctly, it is easier to see limiting in the visual wave form (because the highest peaks will all peak-out at around the same level) than hear it (because only occasional, very brief transients are being effected). But when not used correctly it can approach the sound of constant clipping similar to unintentional brickwalling.
Compression lowers the extent of the peaks along with everything else above a certain threshold level without chopping the peaks off and making them all the same height. Visually, the hair remains shaggy, just not as long as it would have been otherwise. If you look at enough waveforms you can identify this too, but its not nearly as obvious. Without listening carefully with awareness of all this, it will not be visually apparent if dynamic compression is happening in the recording chain itself, is occurring though the PA system, or is related to how distant the recording position was from the source. A recording made on-stage in close proximity to dynamic instruments (drums!) will be far more dynamic and produce taller wild peaks than one made from a distant recording position.