How can i fix my washing machine?

Can you help please! I have a problem with my beko eco care wma1614w. When i put the washer on it wil fill and start as normal but as soon as the next part of the cycle is ready, its like the knob is stuck and starts clicking. If I manually move it on to the next bit it will carry on. It wil drain On the first part of the cycle but not on the second part before spin and it won't spin either. I want to fix it but just dont know which part has gone to replace it. Please help!