Casting resin on canvas

Hi there fellow artists,

Please help... I feel as if I've searched hundreds of sites now and I am reading so many contradictions over the web. I have my A-Level art exam fast approaching and have nobody to ask about this:/

So...For my exam piece I am looking to paint a canvas with acrylic paint and apply resin over the top for a clear glossy/glass look finish. I am so confused - do I need to apply an acrylic varnish over the top of the painting before the resin? If so, do I need to apply an isolation coat first? I read somewhere that I don't need an isolation coat OR acrylic varnish - just pour it on thicker - is this right?

Please,please, please could you advise me on what the process would be and what materials I would need? I would appreciate it more than you could ever imagine!

So many thanks:)