Hi Cameron. Cattleyas need to be firmly anchored in a container or on a wood mount so that their fragile roots can grow and attach themselves. If the plant is moving around at all in the container, the growing tips of the roots break off, and this will eventually kill off the plant.
I'd recommend you get a wood slat basket, available at any garden center including HD and Lowe's for a few bucks. PUt it carefully in that with some wood chip orchid medium, and fasten it firmly to the basket so it doesn't wobble at all. You can use plastic twist ties or string.
They also need a lot of good light, so if you'll have it indoors for the winter find a nice sunny window for it, preferably direct sun in the mornings. They need a LOT more light than Phals do. Once the temperatures are dependably above about 55deg. outside, you can put it outside, gradually acclimating it to the sunlight. Again a morning sun, afternoon shade position will be good for it. You should flood it about once a week, running lukewarm water over the whole plant until it's thoroughly soaked and water runs out the bottom. Your Spray 'n Grow only has micronutrients, so please go get a little package of specific orchid fertilizer. Dilute to about a quarter strength and spray that on the leaves maybe once a week between waterings too. The Spray 'n Grow won't hurt, but probably won't help the plant a whole lot either.