What do I have to do to get an internship as a quant trader?

I’m currently a 3rd year(final year) physics undergrad in Cambridge university- gonna pursue a 1 year masters next year- and one of my friends had an internship at de Shaw last year that paid a lot of money. Honestly, the prospect of doing that is a lot more enticing than going into academia and making 30k a year.

What do I have to do to secure an internship at one of these places? I am not skilled at programming at all, the extent of my knowledge is cs50x Harvard course and a couple matlab and c++ courses in my university. What should I do to become a competitive candidate and where should I apply?