Looks easy hey 😂 so I bought a seal £45 for my undesit integrated fridge Then when taking the seal out I found the seal was actually fitted On the edge inbetween the outer and inner covers . So fitting was a struggle with 2 rounded knifes I eased the 2 apart then slotted the lipped edge in and while prising with a knife and pulling the lipped edge away I firmly went along and eased it in . Took some hand strength. You didn’t mention there are different types of seals in this world. Fortunately I’m a very experienced maintenance engineer.