Accomplishing this depends on your overall carpentry skills and ability to tackle new things. Do you your homework. Stairs and ballustrade is considered advanced carpentry. Plus there is a safety factor. Do it wrong and someone can get hurt or killed. Every cut must be perfect and every joint must be a perfect fit. If not, your railing system will look bad. There are some good resources on the web. One of the best how to guides is from a stair component builder www.ljsmith.com
. Download it and read it. As far as wood choices go I would use oak. Mailny because the components are readily available at home centers, inexpensive, and other trim pieces are easily had. If you make a mistake on oak it will not cost a lot. Make a mistake with special order walnut parts and you will not be happy not to mention the reorder delays. HD sells most stuff to build a basic railing system so it is worth a visit just to see everything. Better variety is available at pro supply specialists. Hardest part is getting the curved parts to fit well. I did a railing system with no experience and it came out nice. It was definetly harder than I thought and took much longer. I made cutting fixtures for my curved parts. The joints came out perfect. Everytime I walk past it I run my hands over it ang say to myself....."this project came out perfect". It does feel good.
If you can afford it, I would recommend paying someone unless you really want to do it. A good stair pro will be done in 1-2 days. It took me 2 weeks at night. The wife was crazy by the end. I had it quoted and I saved probably 600$ so it was financially worth it.I would probably job it out if I had to do it again.