According to Spectrum News:

Key dates

• March 21: Military and Overseas Absentee Voting begins
• April 7: Deadline to register to vote (boards are open until 9 p.m.)
• April 8: Absentee voting by mail begins (ends May 5, postmark deadline)
• April 8: Early in-person voting begins
• April 29: Absentee ballot applications must be received by local board of elections by 8:30 p.m.
• May 6: Election Day

Early in-person voting

• April 8-11: 8 a.m. to 5 p.m.
• April 14-18: 8 a.m. to 5 p.m.
• April 28: 7:30 a.m. to 7:30 p.m.
• April 29: 7:30 a.m. to 8:30 p.m.
• April 30-May 2: 7:30 a.m. to 7:30 p.m.
• May 3: 8 a.m. to 4 p.m.
• May 4: 1 p.m. to 5 p.m.

Resources

• Am I registered?
• How do I register?
• Where do I vote?
• What’s on my ballot?
• Do I need an ID?

Also, information about being a poll worker in Ohio