You want to say an action is permitted or ask whether it's allowed — the rule or the person opens the way, not the skill or the conditions.
序 · The move
1ask what decides the action: a sanction, the conditions, or a learned skillis it permission that opens the way? then 可以 — if conditions, 能; if know-how, 會
2set 可以 (or 不可以) before the verb phrasedoes 可以 sit right in front of the action it sanctions?
3withhold permission with 不可以, never 沒可以is this a standing rule about what's allowed, not a past event that did or didn't happen?
可以 grants permission — the rule or the person opens the way (這裡不可以停車 says the rule forbids it). 能 reads the conditions — the path is open or blocked (這裡不能停車 says the spot makes it impossible). They overlap, but 可以 sources the yes in a sanction, 能 in circumstance.
可以 asks whether you're allowed (我可以進去嗎 — may I go in). 會 asks whether you learned the skill (我會開車 — I know how to drive). One opens a door; the other names know-how that fits the hand.
withholding permission with 沒: 你沒可以走 → 你不可以走
using 會 to ask permission: 我會不會借你的筆？ → 我可以借你的筆嗎？
using 可以 for a learned skill: 他可以說三種語言（meaning he learned them） → 他會說三種語言
English 'can' and 'may' both stand in for permission, and 'can' also covers skill and circumstance, so learners reach for whichever Chinese word they met first instead of sorting that 可以 is the one that asks whether it's allowed.