can you give me the order of all the (possible) steps in a combat, attack / defend trigger, start / end of combat trigger, assualt shield etc

Here's the full combat walkthrough, in order (Rules 463–466):

Before combat opens: After a move/effect puts units at a battlefield, Cleanup stages a Showdown (if Contested) and then a Combat if opposing units are present. If multiple combats are staged, the Turn Player picks which to resolve first (461.1).

Step 1 — Combat Showdown (464):

1. Start-of-combat / showdown effects happen now (464.2.b) — these are triggers, they go on the Chain like any other.
2. Attacker/Defender are established: Attacker = the player whose unit applied Contested; units gain the matching designation (464.2.c). This is when Assault and Shield turn on — they're passive abilities that apply as long as the unit holds the designation, no Chain involved (807, 814).
3. Attacker gains Focus (464.2.d).
4. Attack/Defend triggers (and any other simultaneous triggers) go on the initial Chain: Attacker's triggers first, then other players in turn order, then Defender's triggers last (464.2.e). Because Chains resolve LIFO, defend triggers resolve before attack triggers. Attack and Defend triggers only fire the first time a unit gains that designation in a combat (383.4.e–f). Reactions can be added to this Chain.
5. The Showdown continues Open — Action/Reaction play alternates with Focus until all players pass, then the Showdown Closes (348).

Step 2 — Combat Damage (465) — only if both sides still have units:

1. Sum Might of Attackers and Defenders using current Might (Assault/Shield bonuses included). Attacker assigns lethal damage first, then Defender (465.2.c). Tank forces a unit to be assigned lethal first; Backline last.
2. Once all damage is assigned, it's dealt simultaneously; triggers from deaths resolve after.

Step 3 — Resolution (466):

1. Combat Cleanup: heal all units in play (not just combatants), then recall Attackers still present if Defenders remain (466.1).
2. Determine combat result — win/lose/"No Result" (No Result can re-stage Combat) (466.3).
3. If no Showdown/Combat is staged, the player with units Establishes Control → clears Contested → Conquer if not yet scored there this turn (466.5).
4. Combat ends: Attacker/Defender designations are removed, "end of combat"/"combat ends" effects happen, and all "this combat" effects expire simultaneously (466.7).

Key nuance: non-Combat Showdowns (conquering an empty battlefield) skip Step 2 and the Combat Cleanup entirely — no damage, no healing, straight to Establish Control.