The Master Data Manager web application is used primarily by administrators to perform administrative tasks. For example, only administrators can create models, business rules, or versions of data. For more information about administrators, see Administrators (Master Data Services).
SQL Server 2017 Master Data Services works only in Internet Explorer (IE) 9 or later. IE 8 and earlier versions, Microsoft Edge and Chrome are not supported.
Can't create an MDS web site?
Check out this Microsoft support article for instructions on how to resolve this problem. Can't create an MDS website through a low-privilege account in SQL Server 2016
The Explorer functional area of the web application is the only area not used by administrators. Explorer is for those who update master data on a frequent basis. These users have permission to the data required to do their jobs.