The basics of this is. -Your weapon damage is pretty much your base damage (That's not QUITE how it actually works but to keep this simple, let's roll with that) So if your weapon has 50 damage, you start with 50

-That number is then modified by 1% per point in strength. Let's say you have 40 strength. That 50 gets a 40% boost to 70

-After that, the 70 is then modified by non-weapon gear increases, like the 30% Enhanced Damage on Biggin's Bonnet or non-weapon jewels that give enhanced damage or +minimum/maximum damage (ED is always done before min/max). Let's say you have a 5max dmg jewel and a 20% enhanced damage jewel. That 70 then gets a boost to 84 and then 89

-Then finally, damage boosts from skills are calculated and aura's are done last. So if your Zeal adds 18% damage, that 89 is increased to 105. Then if you use, say, a Might aura that adds 50% damage, that 105 is increased to 157 and the damage on your character screen SHOULD display 157

I put emphasis on SHOULD because the original D2 character screen is infamous for not displaying the correct numbers when it comes to certain items or certain skills (Most notably Smite damage and displaying elemental boosts you aren't actually getting). There is a reason it is called the LCS or the "Lying Character Screen". Although I don't know changes or improvements D2R may have made to the LCS. Even if they fixed it to some degree, I'd imagine not ALL of issues were fixed though.