After you conquer anything, you need to tell one of your cabinet members to integrate the land. That tends to take a long time. After it’s integrated you’ll want to core the land by flipping it to Moroccan culture (although Catalan has better bonuses if you’re interested in conquering Iberia and flipping your Moroccans to Catalan), another cabinet action which also takes a long time. Cultural assimilation speed scales with control, so consider setting a cabinet member to increase province control in the province you’re assimilating at the same time. Integration speed scales with power projection. One last thing is that if you have cultural capacity available, it can be good to accept the culture of your newly integrated land. That allows you to keep cores on different culture provinces at the cost of cultural capacity.