Update start.md

docs/plan/start.md

@@ -3,7 +3,7 @@
 This section starts with an [overview](/docs/platform_introduction/platform.md) of the TI Planning Tool. 
 First, a brief introduction of the platform itself is given, then we show how to create a new plan and the next three sections describe 
 the functionalities of the different services and their user interfaces within a plan. 
-Then it provides step-by-step instructions on how to [create a new plan](/docs/plan/create_new_plan.md) by following the steps below (note: some [TI modes](/docs/background/modes) only have two steps):
+Then it provides step-by-step instructions on how to [create a new plan](/docs/plan/create_new_plan.md) by following the steps below (note: some [TI modes](/docs/background/modes.md) only have two steps):
 
 * [Step 1: Setup](/docs/services/electrode_selector.md)
 * [Step 2: Optimal Configuration Identification](/docs/services/post_processing.md)