I wanted to recite namaz of our holy imams daily but i realised that some of them are 4 rakah. For example namaz of imam hasan (as). Do I have to divided them into 2 rakah salah or no, pray a salah of 4 rakats? The instruction was no specified and explicit.

All recommended prayers are 2 rakah. Hence, you need to pray the 4 as 2+2