sourdough help plz :)

Hello, just wants to quickly ask, if my starter is stored in the fridge, and I take it out to make bread, how many feeds do I need to give it before I can use it?

Depends on the condition of the starter when it went into the fridge, the refrigerator temperature, and how long it's been in there.  I normally open the jar and examine the starter.  If there is any hooch, I would say it will take about 3 discards/feedings to increase the yeast numbers.  If it smells like wet flour, then let it warm up to room temperature before checking it again.  if it still smells like wet flour, look for a warmer place and let the starter grow as it is too immature.  If it smells right, tastes sour, and has bubble activity, then one discard/refreshment should do it.  If it smells great, tastes great but is flat lined, two discard/refreshments.   Always discard the top of a long refrigerated starter to take a sample from the middle of the starter to feed.  One feed cycle ends when the starter rise peaks and starts to fall or collapse.

Also, I noticed many recipes ask for one cup of starter. So then if I used one cup how would I feed it ( flour/water amounts)?

If it doesn't tell you how to mix the starter, look.  Somewhere there has to be some sort of guidance.  It could be anything but many times they are wetter than 100% hydration.  If no other water is used in the recipe, then the starter will surely be a very wet one.  Usually but not always similar to the replacement instructions.  

For example: "Remove one cup of starter and replace with one cup of water and bla bla bla cups of flour."  You will have to figure the hydration.  Divide water weight by flour weight.  Guesstimate water at 240g per cup and flour at 125g -135g per cup.  Once you know the hydration, it is easy to figure how much to feed it. 

I usually keep 100g of starter in the fridge and then feed 50g each of flour n water for the first feed following Bourke st bakery instructions and build it up with three feeds. Although, this takes time and I end up with too much starter. Although, I recently discovered it's perfect for pancakes :)

I keep 100g starter in the fridge and then remove a teaspoon or 10g to feed 50g water and 50g flour (1:5:5) and that is one feeding.  The rest of the starter stays in the fridge until I decide it is too old and replace it with a fresh one.   If you are going thru 3 refreshments, you don't need so much water and flour, important is to reduce the amount of starter first to 10g before feeding and after the third feeding save 10g to feed and refrigerate.  IF you go 1:3:3 feeding, it will peak faster so you can build faster.  Then take or reduce that to get the amount of starter you need (plus 20g if you slop)  

One thing to keep in mind.  If you don't give the starter enough food, the starter may be too acidic and the yeasts react slowly as if there is no food around.  Give them something to get excited about by raising their pH with more food, and they will hop into action.