How do I determine multiclassing stats for an Artificer

I am making a character for a campaign that is starting soon. The character is going to start out as a Cleric (War Domain) and will multiclass with a Artificer (Battlesmith).

I have looked at multiclassing rules, but I am having trouble making heads or tails of it for a multi-class involving a 2/3 caster (the Artificer) and a full caster (the Cleric).

That leads me to my question: what would a lvl 15 War Cleric/lvl 5 Battlesmith Artificer look like? How many spells per level? How many cantrips? Does the artificers ability to replace cantrips still apply?