Road class in OSM is set based on what kind of road it is. You can look at the wiki for this: osm.wiki/Norway/Highways
There is also a page for the default access restrictions for each highway class. osm.wiki/OSM_tags_for_routing/Access_restrictions#Norway
Those can be overridden by specific access tags. access=*

Fixed it now. Use access tags, not highway class in the future.

Please don't use areas for highway tags it confuses routers that end up using the edge of the area at times.
There are other tags for outlining highway areas.
You also made a duplicate at the helipad by adding an area over the node.
You can draw the outline of the helipad and use that tag, but don't tag it as a highway. Just remmeber to remove the helipad tag on the node.

The ways around the school should probably be highway=footway or cycleway.
The pedestrian value is used for "gågate" or a square in towns/cities.

osm.wiki/Norway/Highways

Tertiary is not really set in stone for Norway so some put it on a lot of roads.
Use of tertiary might encourage more through traffic on roads depending on the router used for the app or website.
I believe some routers actually ignore tertiary due to the variation in use cases.
I've become more cautious using this class as my experience with OSM has increased.

Did the Borgavegen get a separate foot- and cycleway or just a sidewalk?

Wouldn't be wrong setting that part to tertiary I guess. Just don't see the point. Unclassified is between residential and tertiary anyway.

You changed them all from communication_tower to tower. Those two are not the same. The wiki is kind of confusing on this unfortunately.
man_made=communications_tower

Please explain the reason for this change. They were tagged as communication_tower for a reason.

Velkommen til OSM. Eit tips: flytt heller gammal node og ikkje rediger adresse nodar som er automatisk importert frå Kartverket. Grunnen er at mange plassar kan det vere fleire personar/bedrifter på samme adresse.

Hei, vær snill å ikkje ta knekken på lancover relasjonar når du redigerer.

Please don't map residential and private properties like these as leisure=garden. This is more for public gardens

This area where the path is is considered uncultivated land and the freedom to roam applies. There is no law forbidding people to walk this path. Even if its not marked it can be naturally created by people walking the same path over and over. This is what highway=path is used for in Norway, naturally created trails/paths.

Ei adresse kan ha fleire firma, så difor er det ikkje smart å bruke desse nodane. Dei er henta frå kartverket og blir automatisk oppdatert.

Ikkje endre på addressenodar som er langt inn automatisk. Lag heller ein ny node med bedrift og anna info.

Hi, welcome to OSM. Please be careful when editing landcover relations in the future. You made a pretty big mess of things. I have hopefully fixed it all and properly mapped the golf course area.

In case you wonder...

https://www.nyeveier.no/prosjekter/e6-trondelag/e6-ranheim-vaernes/nyhetssaker-om-e6-ranheim-vaernes/

I reverted this actually. Please do not delete data without discussion first.

Please undo this. They have started work on this road now.

Taggen motorroad=yes impliserer foot=no og bicycle=no så det lagar berre meir unødvendig tagging. Er ruteren sitt ansvar å lese denne taggen først.

Ser betre ut no ja :) Ein funksjon du har i høgre klikk menyen er å rette opp bygget så alle hjørnene er 90 grader. Veldig fint så lenge bygget har kun rette vinklar.

Vil anbefale å sjå på JOSM editor om du vil redigere meir seriøst i OSM. Den er meir avansert og kraftigare.

Hei, velkomen til OSM. Husa du redigerte var heilt fine frå før og er feil no. Må tenke på perspektivet i bildet og ikkje berre sjå på taket. Kartverket DOM visar ofte eit betre bilde av omriss. Endring av vegnavn og posisjon på adresser vil ha liten effekt då dette blir oppdatert frå Kartverket. Om det er noko feil så meld frå på rettikartet.no