Where you have a 10-element array, you need to replace that with a 10-element cluster. There should be no arrays in the final cluster - everything must have a fixed size. Once you do that, you can wire your cluster directly to Type Cast, or use it as the Type input and wire a string to it to convert that string into the cluster. For the two-dimensional array of strings, I assume that it's actually a two-dimensional array of chars (bytes) - this is a big difference - and that the intent is to have an array of 32 strings, each 64 characters long, or vice versa. If that is case, create a cluster of 64 U8 values, then put 32 of those into another cluster. The "Array to Cluster" function speeds up this process enormously because you can enter the number of elements you want in the cluster, then create a control from it. To get string data into that format, convert the string to an array of bytes, then use array to cluster. Use the reverse process to get data back into a string from the cluster.
Here I've modified your VI to demonstrate this. In the process I removed one dimension from the string array, so that you have an array of strings, not a two-dimensional array of strings.
LS35_SetFrequency-modified.vi