If you wan't an image then start the raw/old version of DB without using the buddy drop. Then at startup you will see an immage that explains a lot... I have only been able to ever see or find this image by starting the old version of DB... very usefull and very illusive (And you're right, the Wiki is just text and would scare away most newcomers, that picture could definately help explain a lot).
Once you can tell the difference between ties and movement vectors (Shouldn't be too hard) then you should have movement vectors visible, these show you in wich direction a bot is accelerating.
Also try selecting a bot. (you can pause the simulation, and run one cycle forward at a time, this makes it a lot easyer to figure out what's happening.)
When you select a bot you can check it's memmory and DNA and such, and you can see it's eyes, how wide they are and wich way they're pointing.
Also white shots are energy shots, these can be cause by venom or something getting shot.
But to get started I would sugest looking at the F3 league, this one only allows the use of the basic features (you can find a the topic in the Bot tavern).
Theres also some tutorial bots in the F3 league that should help understand how the sysvars work.
Theres also a bot tutorial on the wiki and a page called Sysvars, these are very usefull.
But start with the F3 league, then move on to F2 once you have the hang of it... you should save F1 for last (F1 has no rules so it will be realy hard for you to see why your bot is loosing, it could just be a dirty trick used by the bot you're facing).
In the F3 league it will be a lot easier to understand what is making one bot stronger than the previous (Especialy if you look at the tutorial bots.
The tutorial bots in F3 all have a name and no author, names like Shoot, Body, Aim asf... they're all named after the gene that seperates them from the previous tutorial bot, making it very easy to see what you need in order to get further in the league.
I wouldn't recomend starting with too much fancy stuff, advanced eye systems and all that... get the basics to work before you start on the complex stuff, or you'll have no way of knowing if your complex behavior is benefitial. (Sometimes simple is best, you can check Fruitflies from the F1 league (Can be found in the starting gate), it used to be nr 1 for a while but should be down to 3rd place now because of the sexrepro exploit. Either way this bot should show how a very simple clever gene can be enough to beat most complex bots (I think it's one of the shortest bots in F1 if not THE shortest one, and it's extremely simple, no navigation, no clever eyes, nothing advanced about it, it's only strength is to use a very simple but clever trick.)