Set your bow to the lowest recommended fistmele (brace height). This should be about 7". For wood arrows start with a spine of 40-45#. Leave them full-length for now. Fletch one shaft. Put a point the weight you intend to use on the arrow. Shoot the arrow into a target from about 10 paces. It will probably hit nock left indicating a weak spine (if you are right handed). Remove the point and cut the arrow back by 1/2". Taper, put the point back on and shoot again. If it is still showing weak cut off another 1/2", taper, add point and try again. Keep repeating until you get the arrow to fly straight or very slightly nock left. Cut all the shafts to that length and install points. Or, if you cut back to a shaft length of 29" and are still too weak you will have to go to a spine of 45-50# and start over.
Now, if you have a dozen shafts with nocks and points but only one with fletching, you need to fletch 5 more for the next phase of tuning. Check out O.L. Adcock's website for "Bare Shaft Planing". You will shoot fletched and unfletched arrows to fine-tune your setup.
Aluminums are tuned much the same way. The difference is that you can use a chart to find a starting point in terms of spine and shaft weight. For that matter, carbons are the same except that carbons have a huge range of spine in one arrow. I don't pretend to understand how but it works.
Hope this helps.
John