BE Growth and BE Classic tokens can be bought from the BE website https://bitcoinenhanced.io/. After launch you can also buy and sell the tokens on the Waves DEX (decentralised exchange). To access the exchange you need to create a Waves account. Full details on how to do this are here:https://support.wavesplatform.com/en/knowledge-bases/2/articles/4228-get-started-with-waves
If you have any problems please create a support ticket.
Customer support service by UserEcho