Employment problems, should they arise, should be addressed by you informally first. Try not to ignore them, typically they will not go away unless they are highlighted to someone that can make a difference or provide a 'why'.
The goal should always be to resolve the issue whilst maintaining good relationships. This approach also allows you to withdraw from the issue gracefully should there be circumstances you were not aware of. For example, if a colleague is being difficult your manager may tell you that it is not because of you, they are under increased stress due to factors outside of work. In cases like this, you will not get more details due to privacy considerations. If the problems continue, keep talking to your manager.
There are formal processes outlined in every employment contract to assist with resolving problems at work. Typically these start with “Tell us about it” following which the contract will outline more formal processes up to and including formal arbitration. An example may be concerns raised around health and safety. If cardboard rubbish is left in the fire escape and management ignores it, you might consider then raising it through a formal process. In many cases however it will prove more effective (you have a safer workspace and do not damage relationships) to raise problems informally, always try this approach first.
Tackling employment problems informally minimizes the escalation of problems that occurs when you make a formal complaint or start citing legal arguments or requirements that require a response from your company’s lawyers or consultants. In addition, the subjects of the formal complaint may view it as a personal attack. This is clearly not (and should not be) the purpose, but it highlights that the situation needs to be managed in order to get a positive outcome, whilst not creating other problems.
If something arises during your internship, consider talking to and drawing on the experience of your Work Experience Coordinator. We can support your concerns and/or put them into a wider context and suggest ways forward. We are happy to engage with your employer or support you while you do so.