Sentinel-5P is not supported by SNAP (the software for which this forum exists) you should have a look at the Atmospheric Toolbox and ask questions in their dedicated forum.
This doesn’t exclude that someone from the community will be able to help, or that (see hereafter) there aren’t some pieces of information in this forum that you can try to use… the search function is your friend.
We have had a recent discussion on this forum where panoply was also suggested by Ana B.
Also Falah posted a very nice tutorial (on the use of Atmospheric Toolbox) on this other topic, perhaps this can help you.
On this other topic, Sander working, for the atmospheric toolbox also provides some extra input.