🚀 go-pugleaf

Here's a start.
Easiest method:

-- make a new, empty FM chapter. Insert a blank table.

-- highlight the table cells (including the heading row(s) if you have them). In the Graphics menu, select Rotate. Choose the preferred angle.

Now play around with putting text in the table, and see if it meets your requirements as far as layout goes, how the title works, etc etc.

Now try copying your existing landscape table from the other chapter and pasting it into this test file, to see what happens with the rotation. (to copy the table, use your cursor to highlight the table anchor (the upside down capital "T") which will highlight the whole table, do Ctl-c to copy to the clipboard, and Ctl-v to paste).

Second method:
Instead of rotating the table cells, try rotating the body page text frame (not the master page, the body page).

-- in a test FM file that already has some content on a few pages, insert a blank table somewhere in the "middle" so that you have at least a page before and a page after the table page. Add some content in the cells just for test purposes, make the table several rows and columns.

-- Hold Control down. With your cursor, click on the text frame around the table -- again, this is on the body page, not the master.

-- in the Graphics menu, click Rotate

Now test how the rotated page works with the other pages before/after it, especially if you add or remove content before the table itself, so you see how the rotated page moves (or doesn't move) when content before it is changed.

Also, test how you can (or can't) change content in the rotated table.

Those are two of the most direct ways, but there are gotchas with both approaches, it all depends on what your requirements are, so there are still more approaches depending on how much editing of the content that you need to do.

Let us know how you get on -- rotated tables can be a bit of challenge in some circumstances <g>