New workout

Since I was 13 years old I've had the same workout regiment my father showed me and it never worked for me( IDK why I never decided to change it up). So after I've been out of the gym for a while I decided to start creating my own regiment here's a workout I found on the internet
Day 1:
Bench press 4 sets 8 reps
Incline dumbbell press 4 sets 8 reps
Seated dumbbell press 4 sets 8 reps
Tricep pushdowns 3 sets 10 reps
EZ bar tricep extension 3 sets 10 reps
Lateral dumbbell raises 3 sets 10 reps
Day 2:
Deadlifts 4 sets 6 reps
Lat pulldown 4 sets 10 reps
Barbell rows 4 sets 8 reps
Chin ups 3 sets 8 reps
EZ bar curl 3 sets 10 reps
Hammer curls 3 sets 10 reps
Day 3:
Squats 4 sets 8 reps
Lunges 4 sets 10 reps
Leg extensions 4 sets 10 reps
Seated machine calf raises 4 sets 10 reps
Crunches 4 sets 20 reps
Air bike 3 set 15 reps
Flutter kicks 3 sets 20 reps
Day 4:
Dumbbell press 4 sets 8 reps
Incline bench press 4 sets 8 reps
Close grip lat pull downs 4 sets 10 reps
Seated rows 4 sets 10 reps
Tricep dips 4 sets 8 reps
Tricep kickback 4 sets 10 reps
Preacher curls 4 sets 8 reps
Concentration curls 4 sets 10 reps

My questions
What should I add or change? Should I be doing more? Could I be doing 2 a days, if so what should I be doing during that second trip? What should I be doing the the other 3 days a week or I'm I just going back to day 1 after day 4?

Thank you to anyone that takes the time to answers my questions.

You may want to add some shoulder work in their. Some presses and upright rows. You have back exercises twice and only one real shoulder/delt exercise. May be something to add if substitute.

Max

Thats a lot of volume for someone who is/has been sedentary for a period of time.
I would ease you back in to lifting gradually, concentrating on form for the first few sessions then progressing in weight in the 8-12 rep range.
Pick 2 or 3 compound movements for each body part and design a split that works each muscle group twice a week. Don't forget a 10-15 min warm up on the treadmill. Work in some static stretching on separate days. Good luck.

I will definitely be sure to add those in thank you

I will be sure to add those in thank you

That's really good advice thank you.