Here the first card is led by the player who opened the bidding — that is, the player to the dealer's right — regardless of who ended up becoming the declarer. The exception is beggar, where the declarer always leads.
I would like to know how it works under your rules: is the first card led by whoever opened the bidding, or by whoever took the contract in the end?
And do you have a contract of your own where an exception applies?