I'm new to modern logic, and have been reading introduction-level books for about the last six months or so. The Logic Manual is one of the better ones, but perhaps not for starters; I think Tarski's Introduction to Logic is an excellent place to start, then Jc. Beall's Logic, and then possibly the Manual or Lemmon's intro book. I read the Manual before Lemmon and Lemmon's natural deduction proof system was a breeze, but that's mainly because the Manual's natural deduction system was less than clear until I used the associated on-line lecture notes. Those combined with the manual led to a bit of an "ah-ha" moment. Basically I think Halbach provides a bit less than full disclosure in his explanations, or is assuming some basic level of knowledge of logic of his readers. Without Tarski (at least) I would have been at a complete loss with the Manual; with Tarski and Beall (both 5 stars) I still had a bit of an issue, but only really with the natural deduction proofs.
Having access to the on line materials is certainly a plus with this one, and I highly recommend it as a second or third read for those new to philosophical logic.