JISA- Junior ISA- how do you open a JISA?

You start the application in the Parent account.  Select Junior ISA, and progress as usual. Step 2 allows you to add the child's details:

NOTE: The nominated bank account for a JIA must be that of the Parent(s).

(see below for details of how grand parent contributions can be handled)

Q&A re: Grandparent contributions:

Q: Can a DDM be set up within that JISA, from the grandparents' bank account?

A: Yes, we can accept contributions (both single and regular) from the grandparents' bank account. For a regular contribution, the bank details would need to be added by ourselves, including an AML check, as a secondary bank account that we are able to receive funds from.  

If this is required please request via the Freshdesk system.