I’m afraid you’ll need to be brave and twiddle with those knobs - the one with the springs on is the scotch tension device, and that’s what makes your yarn wind on to the bobbin...the thicker the yarn you’re spinning, the tighter this needs to be. I don’t have a traveller, but i assume the springs are the same on most wheels, and i’ve had mine stretched to about 3 times its normal length when i’ve been spinning very chunky yarns....and when i’m spinning laceweight the spring isn’t stretched at all.
If you can’t get the hang of the tension and the drafting at the same time, give up on the drafting for now, and just try ‘spinning’ a ball of commercial yarn, practising treadling and playing with the tension so you can feel how tight it needs to be to start to get the takeup you want. You can also practise pinching off the twist and seeing how you can keep the top part of the yarn twisted, but not let this twist go beyond your fingers if you don’t want to.
I’d recommend winghams for fibres: http://www.winghamwoolwork.co.uk/ they have a wide range and are the cheapest i’ve found. BFL is good for beginners, and merino is also good if you’re one of the people whose yarn keeps bunching up and won’t draft smoothly...if you find your yarn keeps breaking then merino isn’t for you yet, as its slippier than some other fibres.
If you’re on Ravelry, join the UK Spinners group, there’s plenty of people there who can give advice and encouragement, and a huge list of recommended suppliers of fibres and other bits and bobs.