Welcome. As intro pieces, I really like Making Beliefs Pay Rent and Belief in Belief. The rest of the Mysterious Answers sequence is attempts to illuminate or elaborate on the points made in those two essays.

I was less impressed with "A Human's Guide to Words," but that might be because my legal training forced me think about those issues far before I ever wandered here. As a brief heuristic, if the use-mention distinction seems really insightful to you, try it out. If you've already thought about similar issues, you could pass on it.

I think the other Sequences are far less interestingly novel, but some of that is my (rudimentary but still above average for here) background in philosophy. And some of it is that I don't care about some of the topics that are central to the discussion in this community.

As always with advice like this, take what I say with a substantial grain of salt. Feel free to look at our wiki page on the Sequences to see all of what's out there.