You can set position as shown above.
-or-
Best practice for endstops is to wire each switch "Normally closed" and set the configuration M574 blah blah S1, where "S1" is "Active High". This allows the detection of a broken wire or connector (the endstop will appear triggered).
For setup, before you even have endstops wired, invert this. Set the M574 S0. This will cause the endstops to appear triggered all the time... this will cause a home (G28 or similar) to instantly complete with no errors. After the machine thinks it is homed, you can move, etc.
I use this trick a lot when setting up new machines.
Just don't forget to put M574 back to S1 when you do actually wire the switches. And always test them with your finger (observing the web interface, or M119) before you do the first home.