Plug the measurements of your current hub and rim into a spoke calculator. Then plug in the measurements of the new hub and rim. See if the required spoke length is close, within 2 mm. Try changing number of crosses on the new hub, like 3x to 2x. If you can find a match, disassemble the front wheel, sorting the spokes by head in versus head out. Rebuild wheel, keeping head in spokes that way and head out spokes that way. Otherwise, buy new spokes and rebuild. The sorting is not critical but is a nice thing to do.