Making Multiple Line Graph with Textbox Data

Hi! I'm using the ChartMakerPlus to create a graph-analyzing app.

Topic for my app:
Hypertension data recording

Briefing about my plan:

  1. Users can type the systolic and diastolic data in textboxes
  2. The data will saved once the "SAVE" button is clicked
  3. The recorded data will be analyzed in multiple line graph

The problem that I am facing:

  1. The lines are not present although data is saved
  2. Runtime error (refer the picture below)

Here is the png of block for my app:
blocks (2)

Can someone help me to check what's wrong with my block please? Greatly thanks!

global Years is not set as a list, just a number....