Customize Master Page

[AnaUser]

Hi everyone,

I am creating a new intranet site using SharePoint 2019 On-Premises with a lot of branding. One of the tasks is create a fully customized left navigation menu as in this image . 

Any link  or sample would be appreciated.

Many thanks,

[#2]

Are you going to use modern SPO site or classic ones? In the case of classic ones, there is not a problem achieving that degree of customization. However, if you are thinking on modern pages, you must follow some specific rules in regards of customizations

[#3]

Hi Juan,

I will be using the modern sites.

Thank you for your support,

[#4]

@AnaUser There is no masterpage for Modern Sites. It's also not recommended or supported to change the layout of a modern site unless using the provided modern page layouts/sections.

Given the screen shot you provided, it's going to be difficult to do what you want to do in a Modern Site in a supported way. 

[#5]

@Beau Cameron , thank you for reply.

In case I switch to classic sites in order to execute the shared design, any link or sample that I can use for guidance?

Much appreciated,

[#6]

@AnaUser My recommendation would be to go back to the customer and work through mockups that are supported in the modern environment. 

However, if you are hard set on implementing something like this in the mock up, the docs.microsoft.com site has all the resources you need. Be prepared, it's A LOT of reading. Also note, that not all the information is going to be on this page, but you'll to click through the links in the Terms and Concepts section, to get a full grasp of what you are trying to do.
https://docs.microsoft.com/en-us/sharepoint/dev/solution-guidance/sharepoint-site-branding-and-page-...

[#7]

@Beau Cameron , Great!

Many thanks for your reply.