When fixing ceiling panels it is usually best to use a combination of adhesive and staples (if the sub-surface if suitable for staples). To make sure the first panel stays in place you can apply Gripfill / No More Nails etc using the "contact adhesive" method using .
Test your panel to make sure it fits, put blobs of adhesive on the back of the panel, fit the panel into place and then remove it. You will then have some adhesive on the ceiling and some on the back of the panel. Leave the adhesive go tacky and the re-fit the panel - you should get an instant "grab" from the adhesive.
Alternatively you can use laths or bamboo sprung into place to hold the panels while the adhesive sets (use a piece of scrap panel or plywood to ensure the wood doesn't mark the panel).
