While people become less contagious over time, they are still contagious with COVID for an average of eight days. That may vary depending on factors including underlying health conditions and the severity of illness.
Stay home for 5 days after your positive test if possible. Consider return only after major symptoms have resolved. Remote work should be utilized when available during recovery. Follow any specific policies your employer has established.
There's no specific time limit you need to avoid contact with others. You can use 48 hours as a rough guide. If you have respiratory symptoms: stay away from people at increased risk of becoming more unwell from coronavirus.