X:\Steam\steamapps\common\left 4 dead 2\left4dead2\cfg
make a new file called: autoexec.cfg
And the following into it, can adjust if you want later... ..when in game use the console and type "exec autoexec.cfg"
bind "F5" "fortspawn_menu" // Fort Spawn Menu
bind "F6" "fortspawn_load"
bind "F7" "fortspawn_save"
bind "-" "fortspawn_move x 10" // Move Object X +10 point
bind "=" "fortspawn_move x -10" // Move Object X -10 point
bind "[" "fortspawn_move y 10" // Move Object Y +10 point
bind "]" "fortspawn_move y -10" // Move Object Y -10 point
bind "uparrow" "fortspawn_move z 10" // Raise Object +10 pt
bind "downarrow" "fortspawn_move z -10" // Lower Object -10 pt
bind "rightarrow" "fortspawn_rotate 15" // Rotate Object Clockwise +15 degrees
bind "leftarrow" "fortspawn_rotate -15" // Rotate Object Anti-Clockwise -15 degrees
bind "Del" "fortspawn_ang 90 -90 90" // Change Orientation x Angle (stand Up)
bind "End" "fortspawn_ang 0 0 0" // Change Orientation x Angle (Lie Down)
bind "pgdn" "fortspawn_ang 90 90 90" // Change Orientation x Angle (Lie Down Flip 180)
bind "Ins" "fortspawn_ang 90 0 90" // Change Orientation y Angle (stand Up)
bind "Home" "fortspawn_ang 0 90 0" // Change Orientation y Angle (Lie Down)
bind "PgUp" "fortspawn_ang -90 0 -90" // Change Orientation y Angle (Lie Down Flip 180)
bind "BackSpace" "fortspawn_remove" // Remove a spawned object
bind "," "fortspawn_item d a models\props\de_train\chainlinkgate.mdl"
bind "." "fortspawn_item d a models\props_buildings\barn_steps.mdl"
bind "/" "fortspawn_item d a models\props_crates\static_crate_40.mdl"
bind "'" "fortspawn_item p a models\props_junk\gascan001a.mdl"