First download the BD help filess at the top of these forums, they contain every command work used in DB with an explination of what each command word dose.
The best place to start, is by doing. You can read books till your blue in the face, but there is no better way to learn programming that by typeing in code LINE by LINE running it repeat and rince.
Start off by haveing a look at the demos supplied with dark basic. Play the game for a bit, then load the DB file in DB so you can see the code.
Copy and past the whole code into a word program like MS word or Notepad and print it out.
Now here is the bit that sounds dumb, start a fresh project and start typeing in that game line by line.
as your typeing each line
Yup i know the game is allready typed out, but you wont learn anythign stareing at pages of code.
after you type each line of code, useing the BD help files you have down loaded and printed out into a nice book, look up each of the command words and read what they are actually doing.
typeing in each line really drives home into the brain what you are doing. After the code is written out again, make sure you have all the files assosiated with the game (the bipmaps, modles sound files etc), put them all in the same folder along with the code and run it.
And if ya typed it out ok it should run just fine.
TRhen find another game and do the same again.
After a while you start to make sence of the code and start understanding what each line is doing.
There is no short cut way to learn programming it takes time and practice. this is the best way.
After you ahve done a few of these you should start getting a little grip of what dose what.
Next think up of a really lame game idea, lets say walking around a place with 4 walls and shootnig stationary objecst that are placed about and geting points for each one you shoot.
Sounds lame yes, but it will introduce some basic game programing pricerples, controlling characters, shooting, scoreing points, placeing objects.
ask on these forums on ways to do things, then start adding to this lame game. Make the objects move about so they are harder to hit. Then make them so they fire back at you. Introduce a health bar that depleast each time you are shot.
See as you take each little step you will learn more commands and ways to do thing.
Be pacient and soon you will be able to make a fairly simple game all by yourself. When you can do that the sky is the limit, its just about appllieing what you have learn to overcome mroe complex ideas.