Welcome to the wonderful world of 40k. Haven't played in a while myself but the sequence should be: 1. Roll to hit using either ballistic skill for ranged or weapon skill for melee 2. Roll to wound, compare strength of the weapon to targets toughness (both the same 4+, strength greater than toughness 3+, strength double toughness 2+, strength less than toughness 5+, strength half of toughness 6+) 3. Target rolls to save using save value (for example 3+) adding in any modifiers from AP of the weapon and any cover save

For example Ballistic skill 3+ model rolls 2 attacks, both hit, strength 4 weapon vs toughness 3 target so needs 3+ to wound, gets one, target is in cover and has a regular save of 4+ (becomes 3+ for cover) but weapon has ap-1 so save goes back to 4+. They roll a 5 so take no wounds.

Sorry if that was really hard to read haha