Yes you do have to wait on sqm to appear and you do need to do the tar trial first. You need to wait for all the messages and to be on this mission. I'd check your quest log too..
" can start most cult missions by going directly to the cult hideout, however, it's a good idea to first visit Gerimor in Feyrist, offer your help and them ask about all cults he mentions. By doing so, you'll have all cults opened in your Quest Log and it will be easier to track your progress. You can do all the cults access and bosses in any order, but you must defeat all bosses at least once to be able to do the final mission."
The Tar trial
Walk north-east until you reach the tar area. Fight your way to the end of this area until you reach a special tar tile, here, don't step on it yet. As you move through the tar pits, you will see the following messages:
As you enter the tar pits, you feel the heal around you rising dramatically. Survive the heat long enough to prove worthy.
Your body is heating up, the air around you is flickering. (twice or more)
The heat is now unbearable, the blood in your body feels like lava. There's almost no strength left in you - act quickly!
As soon as you see the last message, step on the tar tile. You should then receive this message:
Embrace the stigma of bad fortune. The tar does not feel so hot anymore. You passed the tar trial.
Now you must run to another tar tile, located behind a sealed door, here. If you take too long, you will fail (The tar covering you has cooled down and fell off for the most part. Your body us not heated up anymore.) and will have to go back to the tar area again and start over. It's recommended that you kill the creatures on the path beforehand to make this part safer. If you step on the second tar tile before the tar melts from your body, you should see these messages:
You are now ready to prove your worth. Take heart and cross the threshold of tar.
This means you have completed the tar trial and are ready to move on.
The Sulphur trial
This trial works very similarly to the tar trial. First, go to the walkable sulphur tile here and wait for the four messages before stepping on it:
First message (?)
The sulphur is burning your skin. You almost feel your body melting away in acid. (twice or more)
The acid burning is now unbearable, your skin feels like a sieve. There's almost no strength left in you - act quickly!
Once you step on the sulphur tile, you will see this message:
Embrace the sigma of vanity. The sulphur does not burn your skin anymore. You passed the trial.
Just like before, run to the other tile here. Again, it's a good idea to kill the creatures on the path before running to save time. If you are succesfull you will see this message:
You are now ready to prove your worth. Take heart and cross the threshold of sulphur.
After passing both trials, you have to purify your body. Walk to the cold area to the water here. Once again, wait for all 4 server-log messages:
As you enter the icy cavern, you feel an unnatural frostiness. The ice cold air stings in your face. Survive and prove worthy.
Your body temperature sinks. You can see your breath freezing in the cold. (twice or more)
The icy cold is grasping to you. You can barely move anymore.
Step on the small bridge to wash yourself:
You are now washed and ready to purify yourself in the chamber of purification.
Now go to the purification chamber south-west (here) and walk past the energy gate. Your character will die, but don't worry, you will not lose any experience, skills, items or blessings.
The Powerful Relic
Go back to the cult area in Ab'Dendriel. You now must absorb the power of 10 Barkless Markings' hanged on the walls around this cave. The first symbol is located right next to the Mystic Flame, here. The second is inside the building next to Tigo, here. You will also find three symbols at the trial area (map). The remaining 5 symbols are west of the trials area, past the sealed door (that you should now be able to open), here.
Now head to the large room in this area and use the Cult Object in the center of the room (As you reach out to touch the cult object, a surge of energy bursts from the skull. You banished its power.). Finally, you have access to the boss room.