It’s really hard to describe the actual trail. We do know there’s a marker in Atwater Village identifying the trail, but if you don’t know what it looks like, you’ll probably walk right by.
There’s also signage along the trail in Crystal Springs… if you walk between the fence marking the golf course, and picnic area (starting just east of the Visitor Center) eventually you’ll come to an intersection going north south paralleling the 5 FWY. There’s signage at the native garden next to the golf course so it’s much easier to spot… https://friendsofgriffithpark.org/the-anza-trail-in-griffith-park/
also… https://www.alltrails.com/trail/us/california/griffith-park-explorer-segment-4-anza-autry-main