How can edit my local tile server without uploading changes to openstreetmap server?

Thanks for your answer.I have set up OpenStreetMap web site.In order to see my own map not openstreetmap's , I changed the file vendor/assets/openlayers/OpenStreetMap.js, adding "http://localhost/osm_tiles/${z}/${x}/${y}.png".Finally I could sign up and login to my localhost:3000 page.But when I edit something, the save button says my changes will upload to openstreetmap server.Could you speak more specifically how can I import existing OpenStreetMap data into that database using Osmosis and make changes on that database with standard OSM editors. I really need your help!!!This question has bothered me for a long time.Thank you very very much!!!

I think you don't have to be bothered by the "will be uploaded to OpenStreetMap" message - surely you are using a different account/password with your local server than with OpenStreetMap, so even if you did something wrong, it will not be able to upload anything because the password is wrong. -- For loading OSM data into your local database, see https://help.openstreetmap.org/questions/50109/loading-data-to-apidb and make sure to start with a very small amount of data first, to get an idea how long it takes.

Firstly,thanks for your help.But I met new problem.I use this command "osmosis --read-pbf /home/yeager/Downloads/beijing_china.osm.pbf --write-apidb host="localhost" database="openstreetmap" user="openstreetmap" password="openstreetmap" validateSchemaVersion="no"" But it failed says that "org.postgresql.util.PSQLException: FATAL: password authentication failed for user "openstreetmap"".I just follow the guide on openstreetmapwebsite install.md. after I installed it I could find two new database one called openstreetmap the other osm_test. these two databases's initial owner is my username. Then I creat a new user named openstreetmap and set the unix password "openstreetmap".Then I alter the two databases' owner to new owner openstreetmap. So is there somewhere wrong?

Try this:

sudo -u postgres psql openstreetmap -c "alter user openstreetmap with password 'openstreetmap'"

I find it strange that you have only two databases, and not a third called "openstreetmap_dev" which used to be created also. If you stumble over the lack of this database later, you might have to debug why it wasn't created, and maybe created that by hand (it has the same structure as the openstreetmap database).

Thanks very much. With your help I successfully import my osm data to my openstreetmap database. I was very glad. But afer I opened my browser and typed localhost:3000, I saw the slippy map, not only my new database,but all over the world, Could you please tell me why this happened? I just cannot see any differences between importing data to database openstreetmap with not importing data to database. Another thing is strange, when I click "edit" button ,I did some changes to my map and saved it, But I can only see changes in edit page, In my initial log in page I cannot see any change.