I've not done that but I would think that there should be some timing marks on the shafts with the crank lined up on TDC. I had read some instructions sometime in the past when I was thinking of changing the cams on my Dakota, best I remember did not seem too difficult. I usually do a Google search on stuff like this, lots of info out there.
Well its back together and took me a week. What a nightmare the ovhc was nerve racking and making sure the valves didnt hit the pistons because there is NO tollerance. I changed both head gaskets and water pump, thermostat since I had almost the whole motor appart.