Gasket advice please

upon re assembly of my engine st70 6 volt dax , not that the model makes any difference , should gaskets be fitted totally as the come out of packet or greased or some sort of sealer used ? never really got a cast iron answer on this issue so thoughts would be appreciated.Thanks

Just use them straight out the packaging.
Only for very complicated gaskets people often apply a tiny bit of sealer to keep the gasket in place.

You can apply a small amount of grease to one mating surface if you want to be able to separate the joint without destroying the gasket in the future. For second fitting use a little jointing compound to maintain the seal.
The recommended method is as Waynus stated but this 'trick of the trade' is worth considering if you think you may need to remove the casing again