This means plan a 'fair test' (without any help from your teacher).
A fair test means you find out how one thing changes when you only change one other thing.
Always try and make a prediction saying what you think will happen and why.
The right equipment must be selected for the right job. Often there is a choice and you need to make use of the equipment that is best for your particular experiment. You should be able to use any piece of equipment you can remember having used before. So if you think you need it, ask for it.
Instead of an experiment you may plan to collect evidence using computer simulations, by searching the Internet, etc.