Deploying CraftCMS to Digital Ocean
I would suggest to read through the following articles:

https://nystudio107.com/blog/multi-environment-config-for-craft-cms

https://nystudio107.com/blog/database-asset-syncing-between-environments-in-craft-cms

About reinstalling craft on your droplet and uploading the local database:

the craft install i used in my local dev environment will be pushed onto the droplet, like this i can assure that it doesn't differ in any of the enviornments. About syncing the database read through the articles it will clear things up. In general all of the articles in nystudios blog are more than helpful. i hope it helped at least a bit.