Ok, fuck it. I was gonna put 1 BTC into this but I guess I'll just leave my investment at 0.01 BTC and go buy some more Byteball instead....
This is what you do:
Make a btc address off site if you want with a 12 word recovery phase. Go to the site enter that 12 word recovery phase. You will now have access to the wallet which has your btc on it. Then just press the send all button if you want to sent it all or enter a certain value and contribute...
Yes, you can use any wallet. The important thing is to have your seed or private key.
If you have that, just sent to the BTC address that is shown on the wallet website (Use Your Own Wallet step).
Regards,
Vlad