Push-pull workouts require that you separate the body into 4 "functional groups"
Upper body Push
Upper body Pull
Lower body Push
Lower body Pull
You then begin training with this in mind, picking 1 to 3 appropriate exercises for each.
Examples:
Upper/Lower push:
Bench Press
Overhead press
Dips
Squat
Upper/Lower pull:
Chinups
Rows
BB Curls
Deadlifts
This is obviously the most simplistic version. It is quite effective, remarkably so. It is also very useful in "reverse", i.e.
Upper Push/Lower Pull:
Bench
OH press
dips
DL
Upper Pull/Lower Push
Chins
Rows
BB Curls
Squats
You would do these on alternating days, i.e. Monday-Wednesday-Friday-Sunday-Tuesday-Thursday-Saturday. You can't do these 2 days in a row, because you can't deadlift and squat on consecutive days, usually.
Upper-Lower workouts tend to be a bit more balanced, as opposed to push-pull, which tend to be upper-body dominant. They also lend themselves easier to performing on consecutive days, i.e. Monday-Tuesday/Thursday-Friday, as well as allowing for weekly progression of "heavy/light" training
Examples:
Upper - Monday (heavy)
Bench Press - 3x5
Barbell row - 4x5
Standing push Press - 3x8
T-Bar Row 4x8
arms
Lower - Tuesday (light)
Squats - 2x10
SLDL - 3x10
leg extensions/curls - 2x15
calves
Upper - Thursday (light)
Incline DB press 2x10
BTN Pullups - 3x10
Seated DB press - 2x10
Chinups - 3x10
arms
Lower - Friday (Heavy)
Deadlifts - 3x3
Front squats 4x5
calves
Don't sweat the exact reps or sets, you make these adjustments as you need. I listed them just as very simple examples, without specific endorsement.
Both of these can fit nicely into a VRI (volume-recovery-intensity) type template as well.