How do I change my iPhotos to the 64bit technology?

You transition to Photos. Launch Photos with the option key held down. From the resulting dialog, choose your iPhoto library. Photos will create a new library from your iPhoto media. Your iPhoto Library will not be changed, though it will be re-named.

It isn't. You will have a new library called "Photos Library", and the fact that Photos can open it.

After you open the iPhoto Library with Photos, the old iPhoto Library will have a different filename extension .migratedphotolibrary instead of .photolibrary. The new Photos Library will have the filename extension .photoslibrary . if you have not set the Finder Preferences to show all filename extensions, you still be able to tell the libraries apart by the different icons.

The iPhoto version will still be showing an icon with a fan of three pictures showing a pink blossom, the new Photos Library will be showing an icon with a flower in rainbow colours.

Click the icon in the dock that looks like a multicolored flower.

How do you launch photos?