Hi and welcome!
You may find the sample meal in our diet guide useful. Please also consider pellets and water hardness for the long term. There are now low or no added calcium pellets brands available.
A week on kale won't do any damage; it is a long term high calcium diet that can be an important contributing factor to bladder stones. Guinea pigs have a naturally highly alkaline urine and are therefore rather prone to urinary tract problems.
Recommendations For A Balanced General Guinea Pig Diet
You may also find the other guides and information in our new owners' bundle helpful and interesting. it ranges from understanding behaviours to interacting with your guinea pigs in a way they understand instinctively to learning what is normal and what not:
New Owners' " How To" Starter Kit