This depends on the size of the vessel, what the vessels activity is, what the vessel is used for and how it is being used. Need more info.
The red light should be on the right side, or port side, of the boat. The green light should be on the left, or starboard, side of the boat.
From dead ahead to 22.5 degrees abaft the starboard beam
Red
Green
When boating at night a red and white light on a vessel tells you that you must give way to the other vessel.
When boating at night, a single white light on a vessel tells you that it is anchored.
If you see a single white light directly ahead at night then you are the give way vessel.
A commercial vessel towing at night displays a white towing light above the stern of the towing vessel and a second white light at the stern of the tow. Additionally, the vessel should show a green light on the starboard side and a red light on the port side, as well as an all-round white light at the stern of the vessel being towed. These lights help indicate the vessel's activity and ensure safe navigation for other vessels.
You are the stand-on vessel but should take precautions in case the other operator doesn't see you.
It depends on its relative bearing and also its proximity.
fishing at night
You are boating at night you see a single white light directly ahead, you should give way by going around the other vessel.