From Saracin: Battle of Xu Chang as Lu Bu's forces. You have to achieve Target 1, which seems hard, but can be made easier with a little gate jumping. Since the gates don't matter for a Target, go to the front gates, take down Cao Ren, then head west and north to the West Fort and take it to get inside and then head for the West Inner Post to gain entry to the main area. From here you can head east and take down Cao Pi and then Zhen Ji and finally a little north to Xu Zhu.
For the other Targets just take down all the other officers while doing Target 1 and then head straight up to Cao Cao to finish him off. Xiahou Dun will show up powered up at some point. Ignore him and finish off Cao Cao, otherwise theres a good chance Dun will get you below 50% if you're not strong enough.