This is ho I start the 707 engines

Animations Panel (SHIFT+2)
External Power..............................................................ON
External Air...................................................................ON

Flight Engineers Station
Battery (master switch)...................................................ON
External Power Switch.....................................................ON
DC Meters Selector.........................................................TR3
Essential Power Source Selector.......................................EXT PWR
AC Paralleling Selector....................................................External Power
Engine Bleed Air Switches................................................ON
Wing Valve Switches.......................................................OPEN
Left & Right Air-Conditioning Unit Pack Switches.................Both OFF

Overhead Panel
Ground Start Selector Switch............................................LOW PRESS
Engine Start Levers.........................................................START
Engine Start Control Switch..............................................GRD

I start them in this order - Engine #3, #4, #2 and #1

After Start
Essential Power Source Selector.......................................GEN 3
AC Paralleling Selector....................................................GEN 3
External Power Switch.....................................................OFF

Animations Panel
External Power..............................................................OFF
External Air...................................................................OFF

And for push back, I do the same as nath2889.

Hope this helps.

Mark