Chain going in opposite direction

I replaced the gear and sprocket kit on my chamberlain garage door opener recently. (See https://www.chamberlain.com/chain-drive-gear-and-sprocket-kit/p/041C4220A). After replacement, the chain seems to be going in the opposite direction for some reason and I can't figure out how to fix it. I didn't change the chain or anything, just changed the gear and sprocket and put a new one exactly like the old one (or at least I think I did). But now when I press the garage door opener (with the door closed), the chain seems to go as if it is closing the door. Therefore, I'm not able to get it to open. I'm totally lost. Please help. Thanks.

Did you reinstall the opener trolley backwards? Stand underneath the garage door operator and face your garage door. Look at the trolley and you should see the threaded bolt that connects the chain should be on the left side of the trolley. If it's on the right side then it's backwards and needs reinstalled. Just look in the operator manual and follow the steps for installing the opener rail to the powerhead.

Thank you for the response. Actually, I didn't reinstall the trolley. (And the threaded side is indeed on the left.) I only installed the gear and sprocket...and I can't imagine how that could have resulted in the chain going in the opposite direction. Please see attached video and let me know if you have any suggestions on what may be going wrong.

Im gonna suggest that you pull the cover and manually reset the limits. They are probably are on the open contact when the door is closed.