Beginners Problem. Setup Question for public hotspot. RB2011UiAS-2HnD-IN

A big Hello to everyone!

To keep it in short, I just bought my first routerboard devices. A RB2011UiAS-2HnD-IN and a Mikrotik Groove 2Hn Groove 2Hn. I also purchased a Draytek Vigor Modem.

The purpose is to be used in my cafeteria as a hotspot. I want to provide to my customers free wifi with limited bandwidth only for the basics (facebook, chatting, web surfing, e.t.c., not download and heavy streaming). The maximum connections-devices won’t be more than a 100.

The modem is plugged to ETH1 (IP 192.168.1.1). In ETH2 is plugged the Mikrotik Groove 2Hn because I want to create a separate wifi network for coworkers and 2 printers (they don’t have LAN ports, only wifi connection). If the signal won’t be enough I will add an extra Mikrotik Groove 2Hn Groove 2Hn for the hotspot.

Until now I’ve made a “typical” setup through WebFig (I do not have console experience). I’ve plugged 4 devices for testing purposes at ETH6-ETH8 and everything works great.

The problem is that I cannot figure out how to make the setup to work! More specific:

1.When I plug the Draytek Vigor Modem after a while internet crash. Any suggestions?
2.How to configure the wifi connections from the router wifi (the hotspot) to work as an independent network? I will set only one general password.
3.How to block the devices on that network so cannot discover each other?
4. How can I make an independent network for the Mikrotik Groove (ETH2) with different password (but I want at this VLAN each device being able to find each other)?
5. If the router’s signal isn’t enough and I will need to add a second Mikrotik Groove to cover the rest area, will I be able to set it up as a repeater of my router wifi network? And if yes, how?

I would like to thank you for any help in advanced!

Yours,
Unleashed82