My suggestion right off the bat is to start with pork, and then use the more forgiving pork cuts at first to build your confidence. Pork is the easiest meat to smoke and do well with.
If you start with baby back ribs or pork butt, you will be ahead of the game. They are easy to do and get right. Then move to beef.
For baby back ribs, why not try what is called the 3-2-1 method? Take your rack or two of ribs, and remove the silvery-white membrane on the back of the ribs by peeling up a corner of it with a knife and then using a paper towel to grab it and yank it all off.
Season your ribs with a pork rub of your choice, and put them on the smoker at 225-250. Make sure your temp does not exceed 250. Let them cruise along for 2 hours, and then check internal temp with a meat thermometer.
If you are up to 150-155 or so, pull it off, wrap with foil, and wrap all that with several towels. If you have an empty, dry cooler, stick it all in there. Let it rest for 2 hours, then pull it back out, unwrap, and add any BBQ sauce you desire, and put it back in the smoker, again at 225 or so, for another hour. The internal temp needs to be 160 for it to be done, and you should be right at this in the hour.
If the meat is not around 150-155 when you first check at 2 hours, close up the smoker and let it rock for another hour and check again. Some smokers take longer than others, and you have to learn what yours will do by experience. Soon, you will just know when to check and pull it, and multiple checks won't be necessary.
3-2-1, then, means 3 hours smoking, 2 hours resting foiled and wrapped, and 1 hour back on the smoker before it gets cut and prepped to eat. With some smokers, it really works out to about 2-2-1. Let temp be your guide.
Now, this is my way of doing it and my suggestions for these baby backs. There is a great degree of latitude in BBQ, hence the disclaimer. But I think if you do this, you will have your first rib success. Then look around here for butt cook ideas. Then graduate to beef.