Your first stop should be with the training provider/ administrator for the award. You should not 'not have a clue'. This is unacceptable and you need to speak to them about what they require, how they want it presented, and ask for support.
I found mine straight forward once I got my head around the wording of the prompts and typical answers.
Evidence. I was told that pictures of 'posing by a piece of work' were not really acceptable. You need to keep copies of dated delivery notes, permits to work, method statements, drawings for the job, test sheets etc... that will form part of your portfolio for each unit. There are 8 units, and each must be done twice, showing progression over time.
You must get completed units signed by a work based recorder. This is someone who is qualified to confirm that the work you are claiming to have done has been done by you. They will be required to give their details and their position on the forms.
Good luck, and start gathering that evidence!