Welcome to the Ranch
There have been several questions about linked lists in the last week or so. Have a look at
this thread, which has a diagram of a linked list in. It’s the thread where I thought it was a doubly‑linked list and it was only singly‑linked. See whether that diagram helps. Draw it on paper, with a large gap between nodes, then insert a node in the gap, with its arrows in a different colour. See whether that helps you understand the workings. You will also realise that things to do with linked lists are easier if you can divide them into smaller parts. Similary for diagrams. Start with a diagram for singly‑linked lists before you try anything for doubly‑linked lists.