Be sure you have the correct syringes to use with Lantus, they are different from the U-40 you use with the Vetsulin.
This might be a good time to familiarize yourself with Lantus and how it works. Read the yellow tagged stickies at the top of this forum. There is a lot of info, but just start at the beginning. Ask questions, and you will get lots of help. I hope that the Lantus works well for Precious, it's a very good effective insulin for kitties.
Walmart carries ReliOn U-100 syringes with 1/2 Unit marks: 3/10 ml, 31 gauge, 6mm length needle
When you begin using the Lantus, be sure to edit your signature and in the spreadsheet insert a line between the last day of Vetsulin use and the first day of Lantus use. Type in Began Lantus, or something like so people know when that began.