getting up, positioning
Positioning isn't all that hard and don't be afraid of getting out of position when the boat starts.
The board floats so it's never in the wrong place.
Now for your positioning. As you can see to the left you see a man holding a bar (in Holland they call it a boom). This is just used for beginners so that the teacher can see and tell them what they are doing wrong.
You will see that in the water you will have the bottom of your board pointing towards the boat. Then you will get your butt close to the bottom of the board to the point where you don't have to struggle to get it close it must feel natural and comfortable. Normally when holding a handle you will hold the handle on top of the board (watch out for the line going around you or the board).
Getting up
This is only hard if you make it harder then it really is. Firstly do NOT pull yourself up. Wakeboarding boats have a huge engine with lots of horsepower so you do not need extra help to pull yourself up. If you try to pull yourself you pull your upper body in front of the board ending in you falling forward.
Just put the board against the water and while keeping your arms straight holding the line and your board will start to raise over the water, your butt will start to move to the board and then the board will start to level with the water. At this point you can then turn your board in a line towards the boat so you are riding then stand up. Standing is not necessary, you could ride a whole lake without standing up so that comes last.