not sure abut what weight of oil you should use but i recommend any thing from royal purple
It would be best to check your owners manual. That might also have the maintenance interval. If you don’t have a manual, or it doesn’t have the schedule, you can download a PDF version of each here.
Fill level is outlined on page 203, and fluid type is Mercon ATF as specified on page 222. Do not mix Mercon with Mercon V, which is a synthetic. (note 3, page 223) All in Owners Manual
I don’t see fluid change for Manual Trans until 120,000 miles. (page 26 of maintenance schedule) It is under much less stress than on an Automatic Trans.