How do you get Helium tokens?

Could you elaborate on the process of acquiring Helium tokens? I'm particularly interested in understanding the various methods available for obtaining these tokens. Are they mined through a blockchain consensus mechanism? Or are they distributed through initial coin offerings (ICOs) or airdrops? Additionally, are there any specific exchanges or platforms where Helium tokens can be purchased or traded? I'd appreciate a detailed explanation of the acquisition process to gain a better understanding of how one can get hold of Helium tokens.