Who presides over meetings according to Roberts Rules of Order 10th edition

[Guest Juliet]

I don't know the answer 

[Hieu H. Huynh]

Generally, the president presides.

[Hieu H. Huynh]

And you may want to get the current edition.

[Guest Who's Coming to Dinner]

The regular presiding officer is usually called "President," but may also be called "Chairman" or something else. When this person is absent the Vice-President (or Vice-Chair, etc.) presides. When both are absent, or if there is no regular presiding officer, the members elect a temporary chair by majority vote.

[Richard Brown]

3 hours ago, Guest Who's Coming to Dinner said:

The regular presiding officer is usually called "President," but may also be called "Chairman" or something else. When this person is absent the Vice-President (or Vice-Chair, etc.) presides. When both are absent, or if there is no regular presiding officer, the members elect a temporary chair by majority vote.

That is true, but according to RONR if no vice president is present, before the assembly elects a chairman pro tem, the Secretary should call the meeting to order.  The assembly should then proceed to elect a chairman pro tem, presumably with the Secretary presiding until a chairman pro tem is selected.