Skipping naps please help

We are sleep training our 11 month. He did well the first night and even slept for 12 hours the second night. Put him to bed at 8 pm and woke him up at 8 am. So I was trying to give him his first nap at 10:30 am and he cried the whole time. I’m trying the sleep sense training by Dana Obleman. So I checked on him once and tried to get him to nap for 1 hr and 10 min. After he didn’t go to sleep I played with him for 30 minutes then tried again for another hour and 10 minutes. We went for a car ride ... still no sleep. Now we are back home and he’s throwing a fit again, and won’t nap. I know at this point he is overtired, but what do I do?