Clear out the corridor (M4.2) by killing some more bandits, then focus on looting the area. In the fireplace room you'll find a chest (M4.3). There's a barrel in the corridor (M4.5) and a locker in the library (M4.6). In the opposite room search a wardrobe, a locker and a chest (M4.7). In Triss' room (stairs are in M4.4) there's a wardrobe and a locker. In the last room there's a barrel (M4.8).
Hint 20: It pays to pick up all the objects you find. Geralt's inventory is not limited by the weight of the objects, only by their number. When you run out of space, you can leave some objects in an inn and take them out in another inn - for free. The inn's container space is also limited.
In a chest (M4.9) there's some Calcium equum that you need. You'll also find a book on frighteners there. When you read it (right-click the book in inventory screen), you'll learn some info about that type of monster.
Hint 21: You should read all the books you can find. A lot of quests can only be completed when you have enough knowledge about a certain subject.
At the opposite end of the room there's another locker (M4.10).
In the armory there are three chests. The most interesting one for you is (M4.11) the one with the White Seagull and a book in witchers. There's some equipment in the remaining two chests.
Hint 22: You can't place weapons in your inventory - you have to equip it when you pick it up.
When you have all the ingredients, go back to Lambert (M2.10) and talk to him. You'll get a recipe. Now talk to Vesemir - try to use all the dialogue options to know some more about Kaer Morhen and a witcher named Berengar. You'll also get a leather jacket, a witcher's steel sword, a witcher's medallion, some Celandine, and a scroll on frighteners. Also, talk to Eskel if you want to know some more about the witchers' origins.
Leave through the gate (M2.5) to the courtyard and cut out a piece of the frightener's body (M1.20). You do that just as if you were to pick up an object from a container. You can talk to Lambert once more to know some stuff about fighting styles. Go back to the fireplace (M2.11) and meditate by it. You have to prepare a medicine for Triss. Click the alchemy icon in the upper-right corner, then choose the Cure for Triss recipe. The ingredients will be automatically added, you just have to click the Mix icon in the lower-right corner. At the end, enter meditation state by clicking the hourglass in the lower-left corner.
While you were meditating, Triss was moved to her room. Run to her (M2.9, M4.4) and start a conversation. Notice the "give item" icon near the dialogue options. Click it and then choose Cure for Triss.
Hint 23: Often in the game you have to offer a certain gift to someone before he wants to talk to you. Sometimes that object won't be as obvious as this one.
When you talk to Triss, you'll be able to make love to her. In order to do that, you have to agree to keep her company, and then choose the "nothing to forgive" option. This way you'll get your first collectable chick card. After the love scene, talk to Triss once more to get a book.
You can wait before going to the funeral. Tell Triss that you'll be back when you're ready and go to Eskel. You'll find him in the armory (M4.11). If you talked to Lambert about fighting styles, Eskel will offer you a lesson of hand-to-hand combat. This will commence a quest Qp.22. Fistfight. After the duel go back to Triss or talk to Vesemir.
All that's left for now is to take part in Leo's funeral and say goodbye to Triss. You are now finished with the following quests: Qp.1. Defending Kaer Morhen and Qp.2. A Potion for Triss. You also have the following quests started: Qp.3. Berengar's Secret, Qp.4. Witchers' Secrets and Qp.22. Fistfight.