Trump wants to start his trade war tomorrow

What to watch from a proclamation:

Are any countries exempted? If not, this is a global 25% tariff on steel, and 10% on aluminum.

What, if any, steel and aluminum products are exempted? Past proclamations have listed specific products for targeted tariffs, but they were on different grounds than this round.

What does the post-tariff exclusion process look like? How do they handle the potential exemptions for specific products or countries after the fact?