Starting my journey again!

Hi all,
I've been using MFP (inactively) for a few years now, and the first time round I lost almost 20 lbs. I didn't manage this loss well and put half of it back on in a years time
Now, I'm getting married later this year and I want to be fitter than ever since I've also been diagnosed with PCOS again (due to weight gain I'm sure).
I started the gym yesterday and I'm trying the 1200 calories a day diet, unless I'm working out. I'm trying to mix it up between cardio and strength training. I wanted to know - If I'm strength training, can I use any videos online since I cannot afford a personal trainer at this point. Any recommend videos?

Any tips/advice would be super helpful!

Thank you in advance!!