Katheryn R. have you duplicated the figma kit as your starting point and that is where you've imported your wireframes or no? If not, that'll be step 1 - creating a new figma file using the figma kit which has all the components already in it.
Then you would simply do shift + i to find new components to replace existing ones.
To bulk update across multiple pages, a single component, you can zoom out - select all of the components across all the pages, and then right click "paste as replace" - and it will paste in the replacement component in Figma, with the new one.
There's a few other workflows I do around this after having done a couple dozen client websites using Site Builder, you pick up a thing or two. Let me know if any of these answer your question or if you have additional questions - happy to help!
