Auto Update of Columns based on References

There is a table activities with the below structure.

Name Description Points External?
Whitepaper Prepare Whitepaper 20 FALSE
Case Study Prepare Case studies 15 TRUE
Support RFP Support Response for RFP 25 TRUE

I would like to update the points in form “Tracking” based on the Name that I select and update the Points column in the below table. What is the code that I should specify for auto updating the field and table? The intention is to update points field based on the Points captured from the activities table where Name =Activity Selected in this form.