So say Saturday is the 1st (odd) and Sunday is the 2nd (even). If you choose odd days, you can hunt at the 8am start time and hunt all day till 4pm on Saturday. If you had chosen even days, you cannot hunt until 10am on Saturday but hunt until 4pm like everyone else. This odd/even thing only applies on weekends. Almost all the sites are open during the weekday, everyone can go at the 8am start time but again have to end at 4pm. Typically they release birds wed, sat, sun. Sometimes they do it the night prior.
They break it up the odd and even mornings on weekends in the hopes that the sites are not overwhelmed with hunters.
Site that are not mentioned, you can go at 8am on both even and odd days, because they are typically smaller, draw less crowds and also they release less birds.
Did you download the upland/waterfowl pamphlet? If you go to WDFW, hunting, select species (upland, pheasant) there is another pamphlet that shows all the release sites on the west and east side.
If you got more questions, PM me, I am right in your area and can help you out this year. Welcome to the state and site.