you need to vent it outside or have a very high ceiling, like 6m or so.
I prefer to make them against an outer wall and direct the smoke up and out with a slanted roof. Its a bit of a learning curve as you have to cover the fire or rain will put it out, but it has to vent, or it will smoke everything up and put itself out. Some images online should help, or read the wiki...
https://valheim.fandom.com/wiki/Smoke