If you haven’t ordered your replacement belt yet I would recommend contacting Dave Hughes whose details are in this thread:
https://www.vintage-radio.net/forum/...d.php?p=907961
When I restored my first Philips EL3541 (which has been in my family since new) he provided a very useful kit of parts and instruction manual all for a fairly modest price.
If the Stella is anything like the Philips there will be some friction material under the reel tables that turns to goo. Dave’s kit contains replacements for this and hints on how to clean up the old mess.