ok- you have the filter and pump attached, so that's a good place to start- Was DE already added to the filter?
1. Make sure pump basket is full of water (if empty, you can open the top and fill with water- in an AG pool, it will fill itself from skimmer when you open the top, then secure the top)
2. Make sure no plugs in skimmer and returns
3. if you have multiport valve (6 or 7 position valve at filter) make sure on filter setting. some DE filters have a different valve assembly, but should be a flush setting and a filter setting marked.
4. Turn on pump
5. Make sure water is returning to pool (hold hand in front of return, make sure a good flow is happening)
6. Add Chlorine (bleach); 1 gal of 5.25% bleach will give you almost 3ppm Cl- enough for a start if water is freshly filled and clear
7. If no DE in filter, add your DE per filter directions
8. After about 1/2 hour to 1 hour of circulation, get a good water test
9. Make sure pH is between 7.2 and 7.8 ( some people use 7-8, I'm a little more conservative on pH), if not add acid to decrease or borax to increase. If your pool is 4 foot deep, I'd guess 18k gallons for calculating how much to add (shoot for the middle of the good range initially)
10. after about 1 hour of circulation, get a full test of water and we can adjust everything from there.

That's the quick breakdown, and at that point it's probably good to go if it was fresh water- you'll have to test regularly, and maintain/adjust balance over time, but you can swim almost immediately!
If you have problems (green water, bad smell, get no FC when you test, etc) let us know and we'll help you out!