Right i SORNed my car back in may and now i am taking my test on thursday and want the car to be ready, but it needs to go gets it MOT first

I know that it can be driven without MOT or Tax but with insurence, but how do i unsorn it? do i just insure it and then apply for my road tax and it will automaticaly un-sorn it? or do i fill out forms like i did to SORN it in the first place? then wait for a certificate to say that it is unsorned and then i am free to tax it?

urgh i am so confused >.< someone please help!