Do you have access to our GMAT Navigator program? (I'm assuming you're not taking a live class—you'd have asked your teacher—but if you're doing the Interact self-study program or the Self-Study Toolkit program, then you do have access.)
Navigator contains our own solutions for all of the OG2019 problems (in written or video form—or sometimes both). I would recommend using our solutions, not the official ones.
Navigator is the only place where we post our solutions to the OG problems—we don't post them on the forums. (It's technically not legal to post OG problems online for free and we comply with the law. There are other sites out there, such as GMAT Club, that do post OG solutions for free. Just note that any user can post their opinion, so if a particular post / solution doesn't seem to make sense to you, then skip that post.)