So far we used to have leased line internet connection, now we are switching to Broadband connection. we got a connection also with username and password from broadband provider. I don't know to configure broadband connection with mikrotik router. I called the provider to help me, he asked that my mikrotik router is ADSL or DSL, I asked why they said that they will support only DSL not ADSL.

I have no idea that my mikrotik router is ADSL or DSL or neither.

Can any help me how to connect PPPoE in mikrotik router or Is this possible with mikrotik router?

Details I have is

username:xxxx (from broadband provider)
password:xxxx (from broadband provider)
Systems: 10 systems connected over lan cable with two 8 port switches.
Router: Mikrotik router 750 GL.

Regardless of DSL or ADSL you need a modem.

Regardless of DSL or ADSL you need a modem.

You mean Apart from Mikrotik router I need a modem?

If so the structure would be

Broadband -> modem -> Mikrotikrouter -> switch -> PC

what kind of modem do I need then, I already have belkin wifi router, would it be useful to me?

Regardless of DSL or ADSL you need a modem.

You mean Apart from Mikrotik router I need a modem?

If so the structure would be

Broadband -> modem -> Mikrotikrouter -> switch -> PC

what kind of modem do I need then, I already have belkin wifi router, would it be useful to me?

It depens on your needs and te belkin capabilities.
If you are going for ADSL you have two options.
1) Put the modem in bridge mode and setup PPPoE client from the MikroTik
2) Put modem in routed mode and setup a dedicated IP segment between modem/router and mikrotik.