Run before you can walk
Definition 1 of 1
Pro Tip 1/3Figurative Meaning
It's not about actual running or walking but taking on tasks too difficult for your level. 
Trying to solve advanced problems, he's running before he can walk.
Pro Tip 2/3Novice Errors
Used when someone new at something tries too much too soon. 
She's composing an opera after one music lesson—definitely running before she can walk.
Pro Tip 3/3Cautious Advice
It implies advice to be patient and learn basic skills first. 
I told him not to run before he can walk and start with the basics of coding first.