Quick question about volumes

Hey! I’m having a hard time grasping volumes and how to use them. What does the pathing on each side of the colon mean? I believe it goes something like HostPath:PathInContainer?

I’m working on creating a pi-hole container just to try and learn the basics. They recommend adding these two volumes:
- ‘./etc-pihole:/etc/pihole’
- ‘./etc-dnsmasq.d:/etc/dnsmasq.d’

What does the period at the beginning of the path do?

Can I have Pi-hole use only 1 volume instead of creating 2 somehow?

Can I change the part before the colons to wherever I want them to be located on the host? Example: C:\Users\Server\Desktop\Docker\data\pihole:/etc/pihole and C:\Users\Server\Desktop\Docker\data\dnsmasq.d:/etc/dnsmasq.d

I also heard someone mention named volumes? Is this achieved by doing for example:
If so, where are the volumes stored on the host machine?

Sorry for all of these beginner questions