The new issues usually come out within the first two weeks of each month. As far as the free conditions I'm pretty sure it is just basically sign up for a subscription and cancel before a month is up and you won't be charged.

Can someone tell me when it is released and where to subscribe also the free copy conditions?

...at least, that's the official date the print issue hits stands. The digital edition is typically a couple of days late, but occasionally it's available the same day. I suspect Apple are the delaying factor there.

There are details about the trial on the App Store link to the Edge iPad app.