1. Start with the two curves, one in the control template, one as a background template. For best results have the easier curve in the control template as shown. The curves don't have to be exactly tangential as here, but you will generally get better results if they are at least close to being so (for a curviform V-crossing).
If both tracks are curved to the same radius in the same direction, they won't be tangential, and the result will require a regular V-crossing.
2. You must help Templot by inserting a turnout in the control template, of the correct hand and facing in the required direction. It doesn't matter what size it is, or where in the control template. But the switch size won't be changed, so set an appropriate switch size first. You can change it later if necessary. This one is the default B-6 REA turnout with a B switch.
3. Click on the background template, and then this item on its menu. Choose the appropriate combination of rails for the new V-crossing -- this one is on the inner rail on the control template, and the outer rail on the background template.
4. Confirm that Templot has found the correct intersection position.
5. And choose the curviform option for the V-crossing.
6. This is the result. Notice the odd crossing angle (1:8.65 here) for an exact match. To be prototypical you may want to change that to a normal size (say 1:8.5) using F5 mouse action -- and then adjust the side curve slightly to fit.
7. I added some approach track on the turnout (F3 mouse action), and shortened the side curve to the turnout exit (F4 mouse action). For best results you may want to delete the original side curve and replace it by doing [ tools > make branch track ] on the turnout instead.