walk before you can run

we have to (learn to) walk before we (can) run

One must understand or become adept at the basic skills, techniques, or details of something before moving on to that which requires greater skill or experience. I see it all the time—people who want to become hotshot doctors but don't want to put in all the hard work the field demands. We have to walk before we run, after all. While the results of the drug trial are encouraging, there are still a huge number of tests to be done—we have to learn to walk before we can run. A: "You're having me go to court to defend some drunk driver? Look, I know I'm new, but I want to tackle one of the really big cases!" B: "And you will, but we have to learn to walk before we run."
See also: before, have, run, walk, we

you have to (learn to) walk before you (can) run

One must understand or become adept at the basic skills, techniques, or details of something before moving on to that which requires greater skill or experience. I see it all the time: people who want to become hotshot doctors but don't want to put in all the hard work the field demands. You have to learn to walk before you run. While the results of the drug trial are encouraging, there are still a huge number of tests we have to run—you've got to walk before you can run
See also: before, have, run, walk

walk before you can run

grasp the basic skills before attempting something more difficult.
See also: before, can, run, walk