No problem at all!
I buy the same bags from homedepot/lowes/basspro. I'm going to assume you are using the minion method, if you are not i can explain that or just search for it on here...so assuming you are what i do is put 4-5 fist size chunks on the outside of my coal ring (these will light later on in the cook) and i usually will put 3 chunks in the middle. so this way you get smoke right away and later on as the unlit coals light.
Usually your meat stops absorbing smoke flavor around the 6 hour mark so i'll usually check around the 4-5 hour mark and see if i'm getting anymore smoke, if not i might toss a chunk or 2 into the pit for a little more smoke on the backend.
Usually i dont have alot of extra coal left over...i HAVE saved it before and reused though. If you have a bunch of partially or unlit coals at the end of your smoke go ahead and put those back in a bag for later use. but generally i dont put alot of effort into "putting out the fire" after the meat is cooked. Sometimes at a party people like that smell of smoke in the air.
My vent configuration is this...when the smoker is taken apart and charcoal chimney is getting going i have all vents full open. When chimney coals are grey and ready to go on the unlit coals (re: Minion Method) i pour them on and reassemble the smoker with vents still open. I always have a probe checking the smoker temps (dont trust the built in WSM thermo)...as the temp gets close to 200 ill close all 3 bottom vents to half open to slow the climb. My Top vent always remains full open. When you get to your desired temp (IE:225, 250, 300, etc...) i close the vents to 1/4 open. And this is usually where leave them for the remainder of the smoke.
Once you've closed them to 1/4 open...you'll probably climb in temp a little bit (10-20) degrees but then usually it'll come back down (10 degrees or so). So this is where you want to watch it but once the temp stabilizes you'll usually be able to maintain this temps +/- 10 degrees for 8-10 hours. Again all smokers are different but this is the method i use and it's pretty tried and true.
let me know if you have any other questions. i love my WSM!!