The first step is lacing the wheel without tensioning the spokes. Just get the spokes going through the right holes in the hub and rim with a spoke nipple attached. It's been 40 years since I laced a wheel. It was fun to do.
Here it is with 35 spokes installed. I was shorted one on my spoke order. When I get that last spoke installed then the spoke nipples are turned so that the spokes are inserted all the same amount. That will straighten out the spokes. Then out with the spoke wrench and hand turning the spoke nipples adjusting the spokes to get the rim laterally and radially true. Also checking that the rim is centered on the hub. The red arms on the wheel truing stand check that the rim is true. Then keep tightening until the tension is correct.