Cider is a great traditional base for warming winter drinks. You can bother with recipes but the basics are to heat a quantity of cider appropriate for the number of drinkers expected. Now add a selection of flavourings and possibly some sweetness. If you want to add alcohol do it just before serving, after turning the flames off.
There isn’t much else to say except to recommend spices such as nutmeg, ginger cinnamon, juices such as orange and sweetness from honey or dark sugars.
The additional alcohol can come from brandy, rum, whiskey, vodka… or highly flavoured drinks such as tia maria, ammaretto or others. Do avoid cream based alcohol as it can make the drink look horrible.
Mulled cider at christmas isn’t difficult to make and really helps the christmas spirit come alive.