Hi - and welcome to FixYa
. It sound like your machine is not threaded correctly. Here is the first rule: when you thread your machine, make sure your presser foot is raised up. Never thread your machine when your presser foot is down. When the presser foot is raised, the tension dials open and allow your thread to pass through the dials when you thread the machine. If thread is loose and hard to handle while you are trying to thread, just press down on the thread somewhere near to the top of the machine so it does not slide around. Here is the good news - when you have reached the needle, you can lower the presser foot. Before you thread the needle, pull your thread - if you threaded the machine correctly, the thread should not move. If it does move, you need to start over. If the thread does not move, you can thread you need with the foot up or down, pull the thread
under your presser foot and pull it toward the back of the machine. Leave a 2 or 3 inch tail.
If you don't have your manual, you can download a free copy from the Brother web site. Brother manuals have very detailed, easy-to-read instructions. To get to the correct web page, use the link below:http://welcome.solutions.brother.com/BSC/public/us/ca/en/model_top/HomeSewingMachine/hf_xl3500t3510eus.html?reg=us&c=ca&lang=en&prod=hf_xl3500t3510eus
If you and other readers have a minute to rate my instructions, it helps me to better understand what folks need when they come to the FixYa
site for help.
If you have more questions, or if the link fails, please feel free to comment and I will answer as soon as I can. Good luck, and have fun with your machine!