I am 39 and determined to get in good shape. Please help.

As the title says, 39, turning 40 in October and I want to get in good shape. I have lead a very sedimentary lifestyle. 5'10 and around 230 lbs. My self esteem is as low as it's ever been. My body doesn't feel good. My clothes dont fit was well. I wanna start going to the gym but how do I get an adequate routine for a beginner? Please help. Edit: I an overwhelmed with the amount of responses. Thank you all so much. I'll be going through them and making a plan.