Ready rolled icing. Need a quick answer please.

[BlackCatinaWoollyhat]

I just wondered when I put this on the cake do I need something to stick it down?
Am going to attempt making a hello Kitty shape out of it to go on a Victoria sponge cake.
TIA

To stick it to sponge heat jam to boiling , cool a little but brush over sponge while runny, put icing on while tacky. HTH

How long would it keep for? On and off the cake.
The ready rolled icing?
Sorry if I sound a bit thick it's just I'm a bit of a novice at baking.