You should try to connect "Rotation" output from "Curve To Points" node with "Rotation" input from "Points To Instances" node.

Here is my more complex answer for very similar question:

Unable to rotate instances individually in Geometry nodes

And here are several other questions and answers about rotating something along curve:

Geometry Nodes - rotate point along curve tangent

Align object along curve (Geometry Node 3.0)

Align Instances to Curve with Geometry Nodes

You should try to connect "Rotation" output from "Curve to Points" node with "Rotation" input from "Instance on Points" node.

Here is my more complex answer for very similar question:

Unable to rotate instances individually in Geometry nodes

And here are several other questions and answers about rotating something along curve:

Geometry Nodes - rotate point along curve tangent

Align object along curve (Geometry Node 3.0)

Align Instances to Curve with Geometry Nodes