If an interlinear already exists, you should be able to view it with no problem. From 9.3 (perhaps 9.2) onward, all of the previously created interlinears are stored in the project's meta data, so you will see any previously created interlinears in the drop-down. Just make sure you're looking at the one that the team keeps up to date.
Also, anyone can create an interlinear, so if one doesn't already exist, you can be the one to create it. Paratext will guess renderings to start out with. Some guesses will be wildly incorrect, but others will be surprisingly accurate. If you are even remotely familiar with that language, you can probably pick out words you know and work forward from there. But you should notice if they're using the LWC term or not.
The word parse (morphology) line is the most difficult to do well, because it takes time and a decent working knowledge of the language. Without a good amount of data, I can't accurately guess the morphology, even in languages that are related to ones I know relatively well.