Help with strategy

Hello fellow clowns - hoping I could get a few tips or ideas from y’all about a specific issue I keep coming up against. Currently I mostly play my friend who has Knights and Blood Angles. All he does is move from obscuring terrain to obscuring terrain with his units and then is able to charge my units before I’m able to do much. If I move out he’s safe behind terrain and then I get charged and if I don’t move out, he just moves into the middle, stages and then charges. How can I approach his strategy so I’m able to engage him and do damage? I’ve started to think I should just bring 3x D Cannons.