Because I'm still learning is the best answer I got and I went from starting it letting it idle for a second to working up to 2000 rpm to see what the oil pressure was . Didn't know I wasn't supposed to do that
If it's a flat tappet camshaft, idling is the DEAD WORST thing you can do on a fresh build. Once started, you should bring RPM up to at least 2500 and vary it between 2500 and 4000 for the first 15 minutes, otherwise you risk wiping a lobe and destroying the camshaft and lifters.
When I am "new" to something......especially something that can cost thousands of dollars, I READ every bit of information I can.
