During the course of Baldur's Gate 3, there will be a seemingly endless list of quests to complete, one of which is the Find Mol quest that can be picked up in Act 2. The Find Mol quest title is a pretty straightforward description of what this quest entails, tracking down a Tiefling named Mol.
While visiting the Last Light Inn, Mol can be found hanging around, enjoying some casual downtime. However, once the hideout is attacked, Mol will disappear and the group will look to you for assistance in tracking her down, thus beginning the Find Mol quest. Be warned that without any guidance, this can be a very tedious quest to attempt to complete.
Where To Find Mol
While working through the quest, there will be word that Mol might be found in either the Mind Flayer Colony or Moonrise Towers, but both of these Baldur's Gate 3 locations are going to be a dead end. So save some time and don't even bother searching there.
In fact, it's even more of a waste of time to look for her prior to completing Act 2 at all, because she won't be found until reaching Act 3. Once in Act 3, travel over Wyrm's Crossing and head into the Lower City. This is where Mol will finally be found.
How To Get In The Guildhall
More specifically, look for Mol in the Guildhall. Unfortunately, the Guildhall is a secret underground location which in short just means that it isn't going to be easily accessed. Thankfully, there are a couple of different ways to go about getting inside depending on where you are in Baldur's Gate 3 with other quests. The easiest and most efficient method is to kill two birds with one stone as there is actually a quest in Act 3 that involves getting into the Guildhall and can streamline the process.
For those who are in the process of completing Jaheira's quest to find Minsc, a Ranger class human in Baldur's Gate 3 that actually makes a great party companion and is even an available romance option. Jeheira will eventually lead you to the Guildhall herself.
During that quest, players will be able to track down Tusgront, a guard. If convinced, he will actually open up an entrance into the Guildhall, so keep Jaheira in the party, so she can do the convincing. This is by far the easiest way into the Guildhall, but for those who are not at this point yet in Baldur's Gate 3, there is another way in that's a little more time-consuming.
For this method, head out to the beach that is left of the South Span Checkpoint and help the Guild first. Then travel to the east from Heapside Strand and speak with Tusgront who will allow you to enter the Guildhall, as a friend of the Guild, through the main entrance. There are also backways through the sewers, but all of those options are a little more time-consuming and risky.
Regardless of which path is taken into the Guildhall, there are several ways that will all produce the same result in the end, finding Mol inside the Guildhall. Speak with her to complete the Find Mol quest in Baldur's Gate 3.