questions about 1099 taxes

Ok would try to explain this briefly
Last year I bought a truck and trailer from my friend I gave him $14.000
as a down payment and paid the remaining balance while working under his authority
This year I'll be incorporated on my own beginning next month
So now he sent me a 1099 tax form and while I know I can pretty much claim all the expenses I had I'm getting crazy confused looking at my receipts (I did save them all)
I'm sure you guys have been through this how do I go about keeping items separated (or do I have to do it) by category on recipes for instance you are on the road stop at a Walmart and while you were there you get food a pair of boots a uniform and cleaning supplies for the truck then you pay for this items got your receipt and walk away thinking That's all you just need to save that and when taxes time comes you add up Everything and and done
I'm I supposed to Pay separately for each item
My fear is that since I had more expenses than Proffitt I might just get audited and I just got the 1099 I'd like to file before 04/15
so how do you keep track of what is what on a receipt like food uniforms tax
Is that necessary?
this might sound dumb but my accountant gave me a sheet with a detailed list of all expenses
so even I i manage to decode all the items where do taxes go
Of course I kept fuel scales tolls and all of those separated but places like Walmart and them are the ones that are getting me confused
even at a truck stop sometimes you pay for light bulbs oil log books and food at the same time how do you guys do it
Thanks for reading and any advice

 

Ok i found. A video explaining better the per diem deal that would also help now I think I understand better thanks for your comments