I hate to do this, but you gotta know there's a lot to learn. You working with a number of variables that need to be controlled and adjusted.
Extraction time - which is effected by tamp pressure, grind adjustment and coffee dose.
Extraction time is the time in seconds it takes to get 2 - 2 1/2 ounces in your cup - it should take between 20-30 seconds. (Some do extraction strictly by time, irrespective of how much is in the cup. Not the method I favor, but that's me). If it takes more than 30 seconds, your grind is too fine (assuming you hold your tamp pressure constant) and you are over extracting. You then move the adjustment a click or two to make it a tiny bit more coarse.
Conversely, if getting 2 - 2 1/2 ounces in your cup takes less than 20 seconds, you are under-extracting, and need to make your grind a click or two finer. Again, this assumes you hold your tamp pressure constant.
The nice thing about the grinder suggested is that his has a doser, which means another variable is controlled for you. You will get a consistent amount of grind in your portafilter each time you use it. I suggest using the double shot basket. You will get a single shot basket and a double shot basket. I suggest you use the double shot basket for openers.
Sorry to make sound all complicated, but even casual espresso amking does require a bit time to learn.
Go for it...you'll love the drinks you make!!
Of course of course. I expect this to take months for me to get the process down, not perfected, mind you. I guess I should have said something along the lines of:
"save up, then start learning"