The idea of acknowledgements in a dissertation paper is a way for you to thank all the people who were helpful to you while you were in the process of writing and researching the topic. It does not need to be long, just a single paragraph would suffice but you have to make sure that your sincerity and genuineness is evident in the way you write. The tone needs to remain formal and professional at all times and you should refrain from making it sappy.
You need to understand that not every single thesis paper needs to have a well-written acknowledgement section; your paper will not suffer in any way without one. You should not include the entire acknowledgements portion just for the sake of it and only if you are clear on who you need to thank should you include this part. You can check the examples of papers written by other students to whether they have included one or not and then decide upon what you wish to do.
If you wish to include acknowledgements in your paper but are at a loss about how to write one, there is a very simple solution to your issue. All you need to do is ask your seniors for help. They must have written papers themselves and you can check their work to understand what sort of acknowledgement is accepted by your teacher. The format is the main thing that you should note in this case since most of your dedications are going to be dissimilar.
If you wish to experiment with different formats of dissertation acknowledgements, then you need to check out the Internet. You are going to find plenty of completed papers, all of which have the acknowledgements sections included so that other students can get an idea of what they need to write.