Hello, welcome to the forums !
See this thread, it's for the 3.0 Litre V6, but the procedure should be the same.
The idea is to get #1 coming up on compression and then to stop at TDC.
As the article shows, that is indicated by the Crank Shaft Position sensor pointing to "ZERO" on the crank shaft damper.
When number one is at TDC (and on compression, don't get it 180 degrees out), use your Cam Shaft Position Tool to set where the tooth on the synchronizer goes and lock it up.
It may take a few tries to get things lined up.
How-To: Replace Camshaft Position Sensor Synchro on 1999 3.0V
The manual is terrible, it's incomplete and its instructions are confusing.
When I put mine in, I got the synchronizer close to where I wasn't going to be stressing the wires that connect to the actual sensor ( there is only one position where the wires will be happy)
At the same time you want to line up the tooth (or half moon, which ever one you have) as close to the alignment tool as possible.
Once mine was in the approximate position, I simply rotated the synchronizer a tiny bit until the tool dropped into place.
The other method is to have the tool on the synchronizer in place while you're installing it making sure that the wires for the sensor will reach the synchronizer with out stressing them out.
It's like putting a distributor in and getting the rotor lined up to #1 piston while on compression.
The only difference is that you use the plastic tool to line things up.