Hello Wolverine and welcome to trouble free pools!!
Your pool information needs to be added in your signature under your profile so it is avaiable to help answer any questions.
All you state is that your current plumbing in place is 2". Is your current plumbing PVC, hoses or what? Is it under ground or above ground? Not knowing all of your information I will give you some general answers as to using the PVC for your pool. I just completed a complete change to PVC on our ABG pool.
1.
Measure twice and cut once.
2. Make all of your cuts as clean and square as possible for the best fit. Remove all burrs from cut edges after cutting. You can use a knife blade or a piece of sandpaper to scrap the edge and remove them. Wipe off all fittings with clean cloth before gluing to remove any dirt or dust.
3.
Dry fit (no clue or cleaner)
all fittings and piping before final glueing to make sure it is what you want and need. The fittings will slide in a little further with the glue than when dry fitting them. You can actually measure the distance the fittings and pipe will slide into each other using a ruler. My 1 1/2 inch were all approximately 1 3/8 inches of overlap at every connection. Your 2" may be more or less.
4. Use the proper primer/cleaner and glue for the PVC your using. I like and used the purple primer and clear glue on mine.
5. PVC Unions are very nice to have in place for removal of your piping later if needed (winterizing). They can be purchased at any hardware store that sells PVC. I installed one union immidiately after the skimmer and another at the end just before the final fitting that connected to my pump. That allows me to remove the entire supply line as needed.
6. You should also install a 1/4 turn ball valve in the supply line near the pump end. This will allow you to shut off the water coming from the skimmer so you can clean your pump strainer basket.
7. I am assuming that the fittings that will connect to your strainer and pump will have threaded connections and not be glued. Threaded connections need to be sealed using either teflon thread sealing tape or another type of sealant made for plumbing use. I have used teflon tape on fittings upto and including 2" while other prefer not to use it for anything larger then 1 1/2". See this thread here for more information
http://www.troublefreepool.com/teflon-tape-and-you-t10400.html
8. Last and probably most important is to
make sure that all of the piping and fittings you purchase are Schedule 40 PVC and not the less expensive DWV style that is used for drain piping that is not normally under pressure.
This is just my recommendations and others will probably add some things i may have overlooked or forgot. PVC piping is a very easy DIY project, you just need to take your time, plan your piping, measure, measure again, cut, dry fit and check, glue and enjoy your finished project.
Dennis
...it just may be easier for us to assist if we can visualize it...good luck