Hello!

Server Merging starts with a request that is done through submitting a Request Form. The threads for Server Merge Request (this hyperlink is the latest thread as of this response was made - it is usually updated once or twice a month so always check for it) can be found in News Section. From there, you have to provide information and proof that they needed for your server to get accommodated and evaluated. Once it is done, it will undergo a holding process where they will put your server in the queue and find compatible other servers to merge with yours. This process takes time that's why players should consider prolonging their patience for it. Thank you.

Note: This process might not be the exact way on how they handle Server Merge Requests but either way, it takes time.