New beginner to Greenhouse Gardening

Hi there, I am after some advice. I am enjoying my garden and love just pottering about tending to my plants.
A couple of my friends finally have put my Greenhouse together. I have got a number of health conditions which my immune system has taken a denting and I have difficulty fighting off colds.
So I set my heart being able to grow plants from seed aswell as being able to use the Greenhouse as a Sunroom. This way I can get the Vitamin D from the natural sunlight which will help repair my muscles and build up my strength but by being under glass it will stop me from catching a Chill.
I was wondering if anyone knows of any sites where I can learn about what equipment I will need to be able to succeed in growing my own bedding and hanging basket plants this year.
I have the 8x10 Greenhouse and some staging but would like to know what additional equipment I will need and where I can purchase it from on a low budget to be successful in growing good strong flowers this year.
Can anyone help educate me in Greenhouse living please?