Selling a certificate via Syscoin requires a pre-existing certificate! So the first step is to create a certificate you wish to sell. Once you have the certificate, proceed as if you are selling a normal item.
On the “New Offer” dialog use the certificates dropdown to choose the certificate you wish to sell.
Click “Ok” to list the item.
Once your item is purchase and the payment the certificate will automatically transfer to the buyer. If the buyer chooses to use escrow it is the seller responsibility to transfer the certificate, after which the buyer should release payment.