How long do you have to wait between concealer and foundation?

Excuse me, could you please clarify something for me regarding makeup application? Specifically, I'm wondering about the timing between applying concealer and foundation. Is there a recommended waiting period between these two steps, or can they be applied immediately one after the other? Also, does the type of concealer or foundation used affect the ideal waiting time? I'm just trying to get the best results and ensure my makeup looks smooth and flawless. Thank you for your help!