Welcome to the OW forum. Your questions are still vague. If you can post some additonal details it will help.
Some answers are: Where would you like to go and when?

Yes you can make EXP with a 5 continent ONE, but you will have to take some flights that are seasonal (to ANC) or not interesting (SCL-CCS).

Starting in the USA is probably the worst place to begin because it costs more money and you have only 2 stopovers. If you have FF miles, starting in Poland, Egypt, Sri Lanka, and Thailand seem to be the contenders for cheap fares. Do a search on Warsaw and EMECO for threads related to buying in another country.

Book with the airlines, AA and CX seem to be the best with BA and QF not far behind. Travel agents can be a problem if they do not have experience with the OW product.

This should get you started.