In the first line of a wallet I have entered the address of the purse (HPxUhpdCaXS8tAKvyp7v3bh2KNmyakXY7v). The second a window left empty. I have pressed to sign and I have received the signature. Then I have inserted it without gaps into vote.
Ok, in the second window you must enter the statement you want to sign - for example -
We HOdl that Segwit should be integrated into HOdlcoin without delay.