Microsoft provides learning paths and modules which are accessible at: https://docs.microsoft.com/en-us/learn/browse/?products=dynamics-365
Some of these training materials are composed only of text and some have a video attached.
You can use different filters to get videos and materials concerning only certain product and role. It is equally possible to choose from different levels (advanced, beginner or intermediate).
In case you will sign in, the system will remember history of modules you went through and will suggest you videos and modules you could be interested in.
To begin with Business Central
Introducing BC - fundamental functions
https://docs.microsoft.com/en-us/learn/modules/intro-dynamics-365-business-central/
User interface essentials, search, filter and sort and select data
https://docs.microsoft.com/en-us/learn/modules/user-interface-dynamics-365-business-central/
Fundamental settings
Master data
Master, supplemental and personal data in BC
Finances
How to make the chart of accounts
https://docs.microsoft.com/en-us/learn/modules/chart-accounts-dynamics-365-business-central/
set up of posting groups
https://docs.microsoft.com/en-us/learn/modules/posting-groups-dynamics-365-business-central/
https://docs.microsoft.com/en-us/learn/modules/set-up-vat-dynamics-365-business-central/
No. series
Set up number series
How to personalize user interface
Personalization
https://docs.microsoft.com/en-us/learn/modules/personalize-ui-dynamics-365-business-central/
How to manage users
Set up of users and their roles
https://docs.microsoft.com/en-us/learn/modules/users-security-dynamics-365-business-central/
Dimensions
Set up dimensions
https://docs.microsoft.com/en-us/learn/modules/dimensions-dynamics-365-business-central/
Dimensions and reports
Purchase and sales
Purchase
How to create purchase documents
Prices and discounts
Sales
How to create sales documents
https://docs.microsoft.com/en-us/learn/modules/create-sales-documents-dynamics-365-business-central/
Discounts
https://docs.microsoft.com/en-us/learn/modules/customer-discounts-dynamics-365-business-central/