What exactly do you mean by “new build”?
If it’s an old bike which hasn’t been run for several years:
Fresh oil and filter are a must. Drain fuel tank and fill with fresh fuel. Start up and make sure the oil light goes out fairly quickly.
On a new engine, obviously fresh oil and filter are all taken as given. Start up and make sure the oil light goes out fairly quickly. Run for about a minute or so, switch off and check for leaks. After that start up and run at a fast idle for a few minutes, this helps “bed in” the camshaft and followers, as they can pick up on each other ripping out small bits of metal if run slowly.
In either case do not crank for too long if the engine isn’t starting, it won’t do the starter or engine any good to turn over for extended periods.