Yes the roof seal pushes on to the edge of the roof panel.
Warranty? Dealer should replace
The seal will require shaping to match the front profile , do this by hand and gently push onto the edge of the roof.
do not hit the seal with your hand or any object to try and get it to seat (you will damage the seal inside the recess, which will expose the steel reinforcement and cause the seal to rust)
If there is any rust residue on the roof , from the old seal, make sure you remove every trace before fitting the new seal. (Including cleaning rust from the factory fitted tape) particularly if it is on the painted surface
Allow the roof edge / tape to dry fully before fitting the new seal.
dealers allow 24hrs with the old seal removed, to dry out, before fitting the new seal, appreciate the weather may not allow for this ATM, but dry it as best as possible before fitting the new seal.
A small spray of silicone lubricant applied into the seal recess will assist in fitting the new seal. (do not use anything other than silicone, it may deteriorate the rubber if it is petroleum based , silicone is safe to use on rubber)
Take your time and make sure the seal is fitted correctly before lowering the roof. The important bit is the front profile so it sits correctly. The bonded front corners are used to align the seal correctly on one side , working around to the other , do not stretch the seal excessively, remove and re fit to ensure it sits correctly at the front
Please post some pictures of the failed seal to assist others.