Creating Tab for classical guitar notes

Hello and welcome among us,

The TAB remains blank because, currently, you have two instruments in your score (Guitar AND Guitar Tablature). So, they can't be linked.
In this case, you have simply to copy-paste the content of the standard staff/first instrument in the Tab staff/second instrument.
Result: 1House_of_Rising_Sun_2.mscz (I only change the staff type for the Tab: "Simple" instead of "Common")

Usually, it's enough to create a score for guitar, and in the Instruments dialog ("I" shortcut), click on "Add staff" -> and in last, change the staff type (so, for TAB) in the dropdown list in the right column.
See this configuration in the dialog: 2House_of_Rising_Sun_2.mscz

To begin with linked staves - your first wish apparently - I advice to use first the Template "Guitar + Tablature" available in the New Score Wizard: Guitar + Tablature.mscz
See too the configuration in the dialog (the only difference is the Linked staff)

And so, the result of your file with these linked staves: House Rising.mscz (you can continue now to enter the notes with the desired behaviour)

See also: https://musescore.org/en/handbook/tablature#staff-tab-new-score

As mentioned, you did not create linked staves at all - you created a score for two different guitars.

To create linked staves, start with a score for a single guitar, then in the Instruments dialog, click the existing staff for the guitar and then press "Add Linked Staff", then change the type to one of the tablature styles.

Or, as mentioned, just start out with the the template that is already set up that way for you.