Speed tests - download vs upload speed?

[VTAb182]

I see many people posting speed tests from their phones. Each one has an upload speed and a download speed, and some have ping. What do these mean in terms of how fast processes go in the phone/on the internet? As in, is internet speed affected by one, the other, or a combination?

 

[Minimoose 360]

I see many people posting speed tests from their phones. Each one has an upload speed and a download speed, and some have ping. What do these mean in terms of how fast processes go in the phone/on the internet? As in, is internet speed affected by one, the other, or a combination?