In paragraph form, briefly explain what the purpose of a timeline is

The purpose of a timeline is to show a series of actions within a certain period of time in a chronological order, that can help someone to better understand the change, recurring events, causes and effects, and key events of historical, social, and scientific importance.

Sorry if this does not make sense, I used translate because English is still difficult and sometimes confusing for me.

they wanted the u.s. to fight on the side of the central powers.

the most famous of all the units fighting in cuba, the "rough riders" was the name given to the first u.s. volunteer cavalry under the leadership of theodore roosevelt. roosevelt resigned his position as assistant secretary of the navy in may 1898 to join the volunteer cavalry. the original plan for this unit called for filling it with men from the indian territory, new mexico, arizona, and oklahoma. however, once roosevelt joined the group, it quickly became the place for a mix of troops ranging from ivy league athletes to glee-club singers to texas rangers and indians.