Although this is a simple guide, it's essential that I create this thread so that I don't have to explain how to bonfire in each guide I make. "Bonfiring" is simple, but it can be very important in many situations.
The only requirements for creating a bonfire and receiving a health boost from it are 6 logs and a tinderbox (or 5 logs and an active fire created by another player). However, this technique isn't very useful unless the player has a fairly high firemaking level and somewhat high level logs. In an ideal situation, the player will have 6 magic logs, a tinderbox, and 99 firemaking.
In order to bonfire, a player must first light a fire. After lighting the fire, right click the fire and select add logs. All five of the remaining logs will be added to the fire.
As the last of the five remaining logs is added to the fire, a message will appear in the chat box notifying the user about the bonfire boost.
The length of time that the boost lasts for depends on the type of logs used on the bonfire. The percentage by which the user's maximum health is boosted is based on the user's firemaking level. As shown in the image above, magic logs with 99 firemaking will give the user a 10% maximum health boost for the next 60 minutes.