You can meditate:By asking someone. If that person has a "meditation" icon (looks like Geralt taking a nap), select it. After the raid on the laboratory, Vesemir will have a meditation icon. In Act I, you can meditate at Abigail's place (ask her) or the inn (ask the innkeeper; he'll charge you five orens).At a lit fire. Not all fires are suitable, though. It must be a fire you can activate. The one between the Kaer Morhen kitchen and dining room is suitable. Activate it from the dining room side.By lighting a fire. You can light a fireplace with a flint or the Igni sign. Once it is lit, activate the fire to begin meditation. In Act I, there is a fireplace outside the inn and several around the countryside.