Is there any instructions to download OSM in postgres database?

Is there any instructions to download OSM in postgres database? I use geosuite (geoserver, postgres, postgis). I’d like to download USA and Russia (1-12 levels). I also want to download sld styles. (Is there any standard way).

So, there is intranet. We use geosuite. And I’d like to download OSM with sld styles.