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Dammit
That looks more like it's for repairs like a bitumen in a tin, rather than a fixing / bonding compound.
To stop the thing wandering off (theft / in the wind) you'll need to fix it to something mechanically. You could create upstands then bolt them to the existing the roof surface (possibly ply over a wood structure), then fix the frame in to those. Could just be a block of treated or hardwood wrapped in roofing felt. That cement would be useful to seal it, both to the existing roof surface and where you bolt something to it.