Need AQA Geog 2 Help ASAP!

Hi, basically I have a pretty good idea of most of the things I need to know for my fieldwork section, however there are a couple of things which keep coming up that I don't get, and the mark scheme is no use.

"Distinguish between primary and secondary sources of data used in your fieldwork enquiry." (3 marks).
"Outline how you obtained and why you used secondary data in your enquiry" (5 marks).

My fieldwork was on the River Browney, and am I right in thinking my primary data would be velocity/loadsize/X sectional area as you move downstream?

However I have no idea what Secondary data is, and if anyone could answer those 2 questions for me it would be massively appreciated.

Primary Data refers to data that you have collected and Secondary Data refers to data you have got from other people.In my fieldwork I collected several pieces of primary data like velocity,depth,width,sediment size,sediment roundness,gradient etc for the Glenderaterra Beck.For Secondary Data, I shared results with other groups to increase the nubmer of readings making them more reliable and needing a lower spearman's rank coefficient for the results to be significant and I used google maps/earth which I found from the Internet and ordinance survey maps from the internet to get to understand the characterisitics of the area eg.scree slope,disused mines, the incline of the area, the footpaths I would need to take and the Blencathra Centre I was at used the data I had collected as primary data and calculated hydraulic radius,discharge and cross sectional area making it secondary data this helped save time leaving more time to conclude and evaluate the results of my investigation and the Blencathra Centre gave me the results for a site 4 further downstream as the weather was pretty bad with torrential rain and I was running out of time to collect the results(the last part about Site 4 is made up but this is allowed).