Not sure how to invest in it. Do I understand correctly I just need to send BTC to the address given on the website?
Yes that's correct
How will I get my tokens after launch?
When the tokens are to be released, You'll be asked to log into a facility on the HEAT web site and make another (pre-paid by us) small transaction from the same cryptocurrency account you used to invest. This transaction will authorize you for the HEAT tokens that are transferred to your initial HEAT wallet which is created client side (securely without anyone else getting access to your private key) on the fly during the same process.
Thus you need to just ensure you have access to the same BTC account at the distribution time and you're covered to get the tokens.
If that sounds complex, please contact us privately for other arrangements.