Designing Kitchens and Bathrooms - Shower Grout Repair

I have a few spots in my shower where the grout has to be repaired. I'm also going to clean the grout and seal it. I bought a small tub of premixed grout and a small bottle of sealer. Nowhere on either container does it say how long I have to wait before using the shower. I'd appreciate and suggestions for cleaning the grout; how long to wait after grouting before sealing; and how long after sealing before using the shower.
Thanks

Don't use that "premixed grout". They call it grout but its not. Its really caulk in a bucket. It should never be used in a wet area - never ever. In my opinion it should never be used anywhere. You need to return that stuff and buy a grout in powder form that you mix with water. It will do the job and last a long long time.

Thanks HeresJohnny for the headsup. Could you tell me how long I have to let the grout cure before sealing, and then how long before I can use the shower again

For most grouts you can seal after 72 hours. Check the directions on the grout youre using. Give it 2 or 3 days after sealing before using the shower. Directions on the sealer should tell you this also.