There is no need to preheat the extruder, the extruder doesn't take much time at all to get up to temp. It is most important to get the build plate fully heated and then level it. The plastic platform sags to the front when it all gets heated up.

Under preheat settings on the front panel turn preheat platform to yes and extruder to no. Reason, I don't like leveling the plate with a piece of paper with the extruder at 450F. Also usually when the extruder is fully heated it will seep a little material and this interferes with setting the plate gap.

Order of operations to start a print goes like this. Start slicer on computer so it is running, sometimes this takes several minutes. Preheat build plate. When you start preheating you can back out of the menu and go to home axes, it will still preheat when you go to another menu. Home axes and start getting things set as good as you can using a post it note for setting the gap. It is right when you can slide the note under the extruder with a little resistance. Get all 3 thumb screws set as best you can, you can manually move the print head to the front right and left then back and forth a couple times. The right side affects the left side and vise versa so go back and forth a few times until both sides are good. Then set the back gap. Let the build plate get fully up to temp then check the front again, it probably dropped a little so reset the gap. After all that then get the file copied to the SD card and start printing.

This sounds like a lot to get a print started but it only takes a few minutes to do.

The most important thing not to do is level the build plate again cold and adjust the front, it will just go out of whack again when it heats up.