Option 1 (recommended)
Every 10 seconds > LocalStorage > Set Item "VarName" value of "VarValue"
On Start of Layout > LocalStorage > Check Item Exists "VarName"
Item Exists "VarName" > Set variable "InGameVarName" to LocalStorage.ItemValue
Item Missing "VarName" > Set variable "InGameVarName" to "DefaultValue"
Option 2 (not recommended)
Every 10 Seconds > Save Game
On Start of Layout > Load Game