Any suggestions, nap time routine?

I have a 3 month old baby boy that goes down perfectly at night due to his routine. I am having a hard time getting him down during the day due to my 4 year old being in preschool from 8:15 to 11:45. I try to read his ques and put him down. When it is time for a nap I put on the sound scape music and put him in his swing he will cap nap,and sometimes a 2 hour nap. He seems tired. I still am getting use to having 2 children .