There is no point collecting data if you do not analyse it. You cannot just dump raw data into a Word document and call it an evaluation report. Nobody will read it and even if they tried to they would struggle to make any sense of it.
Your data analysis does not need to be super sophisticated. It is extremely unlikely you will need to do complex statistical analysis. But you do need to go through the data carefully and methodically to work out what your audience are saying and doing. This is particularly the case with qualitative data.
Can’t I just use my memory?
Our memories are a selective record of past events. Strange and emotive things are very easy to recall e.g. where you were when you heard about the 9/11 attacks, or Donald Trump winning the 2016 election. The ordinary, unchanging, common, or not especially surprising is easily forgotten e.g. what you had for breakfast on Wednesday two weeks ago.
The risk of relying solely on what you remember your audience saying or doing is that you will massively over emphasise the tiny minority who said or did something strange and unexpected. There is no short-cut to going through your data and sorting it into categories.
How long will it take?
Up to you - it depends on how detailed an analysis you wish to do. But as a rule of thumb, it will take at least as long to analyse the data, as it took to collect it.
In the accompanying documents we provide details about how to analyse data from open-ended questions used in both quantitative and qualitative research; and how to analyse data from observational studies.
There are many books and YouTube videos about conducting basic statistical analysis on numerical data.