Start with the basics, if you don't already have that.
For you to be able to get the most out of a workout session, you need to have food fuel you before hand.
Have a meal around 2-4 hours before you exercise.
You can find plenty of sources on nutrition online.
Also, stay hydrated. Drink water.
Especially when you're doing cardio, drink water.
Before you exercise, you should always warm up your muscles, as to avoid injury, and minimize needed recovery time.
After you warm up, you should do some dynamic stretching.
If you're not used to stretching, be careful not to stretch too far, as you could injure yourself.
After static stretching, you can then exercise.
If you're not very physically fit, there's no need to lift weights, you've got yourself to lift around.
- jog
- push ups
- sit ups
- core muscle exercise
- pull ups if you can even do them
If you can't do pull ups, you can find some cheap light (2-10lbs) weights on craigslist, goodwill, Walmart, as well as plenty of pother places,
and you can do bicep curls, and rows to exercise those muscle groups.
If you're going to get weights, you can also do other exercises which you can find on YouTube to exercise your other muscle groups.
Generally, it's good to exercise your whole body.
You don't need to do full body exercises, but if not, you should get each muscle group by the end of a 1-week period or so.
After exercising, you should do static stretching.
Do NOT do dynamic stretching, you're just fucking up your muscles with that bullshit.