How Purines Affect Gout?

i have had gout for several years; I am not overweight, don t smoke, don t really drink anymore, if so a few ounces of wine or rum a few times a wk. ; am on a strict diet avoiding purine high foods; I am still confused about uric acid and purines; after reading much on the internet, I still don t understand as follows: do high purine foods and drink, like beer create excess uric acid that is not excreted fast enough, so it forms crystals in the toes, joints etc. is it the excess uric acid that cant be excreted fast enough that creates the pain or the purines? all foods have purines at diff. levels...how is uric acid created from purines? thx jj