What are the answers to questions 1, 2, and 3 about the National Museum and Bamum royalty?

1. Where is the National museum located?
The National Museum is located at the premises of the former presidential palace, next to the Supreme Court and adjacent to the Ministry of Public Health in Yaounde.

$$\boxed{\text{At the premises of the former presidential palace, next to the Supreme Court and adjacent to the Ministry of Public Health.}}$$

2. What is the first thing to do at the gate before entering the museum?
The first thing to do at the gate before entering the museum is to pay an entrance fee and receive a ticket.

$$\boxed{\text{Pay an entrance fee and receive a ticket.}}$$

3. For how long did the Queen mother of Bamum rule?
The Queen mother of Bamum ruled for ten years.

$$\boxed{\text{Ten years.}}$$