Transfer WIndow

@AstroTommy I was doing this a few days ago and eventually just gave up because I didn’t know where to burn at all. But this is still the way to do it, I hope it will be changed or someone makes a chart/graph of when you need to burn in your orbit (around the sun). But knowing it is now just trial and error is nice to know because I had the feeling I was the only one doing this wrong!

@PorkyClown3 Ok so I followed your advice and I finally found an answer to my question so I will lay it out here for the OP here because no one has really answered his question and I was also needing to learn...
This is how you find out where the optimal place to make your burn is: First you create a maneuver node roughly at the place you think it should be, create the burn on the maneuver node until your resulting orbit is kinda close to getting a good encounter and obviously you are a little off and not exactly in the exact perfect location for your burn... But here is the magic trick: if you tap & hold the middle of the maneuver node you will see another icon appear that will allow you to manually move the maneuver node from side to side and you will see your resulting orbit change as you move the maneuver node, that way you can place the maneuver node in the best location for your burn and Bingo! Question answered :D
You're welcome ;-)
I've been wanting to know that for a few days now...

@AstroTommy The one in this game works exactly like Kerbal soace programs, you can watch a ksp tutorial because its thr same thing

@PorkyClown3 yes but the question is WHERE do you make your burn for the optimal trajectory using the least amount of DeltaV...? I agree with the OP, it takes a lot of trial and error when you have to guess it and requires a bunch of corrections later :-/
In another game called SpaceFlight Simulator, there is a feature that when you target another body, you see a little highlighted area in your orbit where you should make your burn for an encounter with the object... Surely SR2 would have such a feature but where is it?

Click on your orbit and make a maneuver node to plan a trajectory

No