Hey srijita . i can understand you situation regarding this .i was totally like you when i was struggling in jobs as career consultant i would definitely suggest.
You need to start parallely both if you want to switch it from sales filed to tech .
initially you need to learn just a basics of programming you can get it via google & youtube after having basic ideas of programming i would definitely suggest you to join some premium & result oriented edtech courses online .
see why i am saying you premium because you are switching a career you are not having degree for tech i.e ( software development ) so make your hard work while earning there are 6 months job oriented online courses you can grab them all
some are providing 2x hike on salary if you don't get a job you don't have to pay any fees for it
Some effective online courses you can opt
khan academy , unacademy & scaler academy .