URL/ File Names

I am going to be migrating a site from Drupal to CMS Builder. Here's the link to the existing site: https://siggins.com/

My concern with the URLs comes from the fact that this site has been published for some time, and we have been providing SEO and Website marketing for this company, including AdWords, and the existing URL for many of the pages has been established for quite some time.

So, I really don't want to create all NEW URL addresses for the web pages; instead, I would like to utilize the same path/URL in CMS Builder.

Normally I would either name all html files the same thing in the website, or in the case of PHP, I create a matching html file from the previous site and redirect it to the new URL with a .php extension.

But, the URL names on the Drupal site don't have an extension. For instance, if you look at one of the links, Services, the URL is https://siggins.com/services. Then, to branch to one of the services the URL is: https://siggins.com/services/design-build.

I have a new installation of CMS Builder and I'm getting ready to create all of the section editors. Does anyone have a solution of how I can either keep the same URL and/or plan to forward the new URLs in some fashion? I do have the Permalinks module installed. If there is something I should be doing to make this work then I need to know while I'm getting everything set up.

Thanks!