Google brings this up:

"Telegraaf will become a member of Autograph Collection Hotels in summer 2017 after Telegraaf has been fully integrated to Marriott’s sales and reservation system.

Hotel Telegraaf is a 5 star luxury hotel in Tallinn, located in the medieval Old Town next to the Town Hall Squre. Building of the hotel was built already in 1878 as a bank and later as an exchange station for the Estonian Telegraph company. Hotel Telegraaf opened its doors in 2007."

From the hotel details in your link, it's got 72 rooms, 11 suites. Valet parking is free, but there's a charge for on-site parking. Public transport is close; 1km.

Your link is from an Australian site. The property isn't showing up on the regular Marriott site yet & it's not listed under new hotels opening on the Marriott site. You'll probably have to keep checking the link or give Marriott a call. Thanks for the heads up on the property!

Cheers.